256716520 has 32 divisors (see below), whose sum is σ = 578291400. Its totient is φ = 102565888.

The previous prime is 256716517. The next prime is 256716521. The reversal of 256716520 is 25617652.

It can be written as a sum of positive squares in 4 ways, for example, as 256448196 + 268324 = 16014^2 + 518^2 .

It is not an unprimeable number, because it can be changed into a prime (256716521) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 35796 + ... + 42364.

Almost surely, 2^256716520 is an apocalyptic number.

256716520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

256716520 is an abundant number, since it is smaller than the sum of its proper divisors (321574880).

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

256716520 is a wasteful number, since it uses less digits than its factorization.

256716520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7557 (or 7553 counting only the distinct ones).

The product of its (nonzero) digits is 25200, while the sum is 34.

The square root of 256716520 is about 16022.3756041356. The cubic root of 256716520 is about 635.5522671861.

The spelling of 256716520 in words is "two hundred fifty-six million, seven hundred sixteen thousand, five hundred twenty".