251555240 has 16 divisors (see below), whose sum is σ = 565999380. Its totient is φ = 100622080.

The previous prime is 251555237. The next prime is 251555243. The reversal of 251555240 is 42555152.

It is an interprime number because it is at equal distance from previous prime (251555237) and next prime (251555243).

It can be written as a sum of positive squares in 2 ways, for example, as 242923396 + 8631844 = 15586^2 + 2938^2 .

It is not an unprimeable number, because it can be changed into a prime (251555243) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3144401 + ... + 3144480.

Almost surely, 2^251555240 is an apocalyptic number.

251555240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

251555240 is an abundant number, since it is smaller than the sum of its proper divisors (314444140).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

251555240 is a wasteful number, since it uses less digits than its factorization.

251555240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6288892 (or 6288888 counting only the distinct ones).

The product of its (nonzero) digits is 10000, while the sum is 29.

The square root of 251555240 is about 15860.4930566486. The cubic root of 251555240 is about 631.2641451590.

The spelling of 251555240 in words is "two hundred fifty-one million, five hundred fifty-five thousand, two hundred forty".