# 240 (number)

(Redirected from 247 (number))
 ← 239 240 241 →
Cardinal two hundred forty
Ordinal 240th
(two hundred and fortieth)
Factorization 24× 3 × 5
Roman numeral CCXL
Binary 111100002
Ternary 222203
Quaternary 33004
Quinary 14305
Senary 10406
Octal 3608
Duodecimal 18012
Vigesimal C020
Base 36 6O36

240 (two hundred [and] forty) is the natural number following 239 and preceding 241.

## In mathematics

240 is:

• a semiperfect number.
• a concatenation of two of its proper divisors (see Sloane's A50480).
• a highly composite number since it has 20 divisors total (1, 2, 3, 4, 5, 6, 8, 10, 12, 15, 16, 20, 24, 30, 40, 48, 60, 80, 120, and 240), more than any previous number.
• a refactorable number or tau number, since it has 20 divisors and 20 divides 240.
• a highly totient number, since it has 31 totient answers, more than any previous integer.
• a pronic number since it can be expressed as the product of two consecutive integers, 15 and 16.
• palindromic in bases 19 (CC19), 23 (AA23), 29 (8829), 39 (6639), 47 (5547) and 59 (4459).
• a Harshad number in bases 2, 3, 4, 5, 6, 7, 9, 10, 11, 13, 14, 15 (and 73 other bases).
• the aliquot sum of 120 and 57121.
• part of the 12161-aliquot tree. The aliquot sequence starting at 120 is: 120, 240, 504, 1056, 1968, 3240, 7650, 14112, 32571, 27333, 12161, 1, 0.

240 can be expressed as a sum of consecutive primes in two different ways: 240 = 53 + 59 + 61 + 67 = 17 + 19 + 23 + 29 + 31 + 37 + 41 + 43.

E8 has 240 roots.

There are 240 distinct solutions of the Soma cube puzzle.

## In other fields

240 is:

### 241 - 249

241 has its own article.

242 has its own article.

243 has its own article.

244 has its own article.

245 has its own article.

246 has its own article.

247 has its own article.

248 has its own article.

249 has its own article.