256664560 has 40 divisors (see below), whose sum is σ = 612880416. Its totient is φ = 99889920.

The previous prime is 256664543. The next prime is 256664561. The reversal of 256664560 is 65466652.

It is a tau number, because it is divible by the number of its divisors (40).

It is a hoax number, since the sum of its digits (40) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256664561) 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, 40396 + ... + 46315.

Almost surely, 2^256664560 is an apocalyptic number.

256664560 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

256664560 is an abundant number, since it is smaller than the sum of its proper divisors (356215856).

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

256664560 is a wasteful number, since it uses less digits than its factorization.

256664560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 86761 (or 86755 counting only the distinct ones).

The product of its (nonzero) digits is 259200, while the sum is 40.

The square root of 256664560 is about 16020.7540396824. The cubic root of 256664560 is about 635.5093852243.

The spelling of 256664560 in words is "two hundred fifty-six million, six hundred sixty-four thousand, five hundred sixty".