256562640 has 300 divisors, whose sum is σ = 953489196. Its totient is φ = 63922176.

The previous prime is 256562629. The next prime is 256562659. The reversal of 256562640 is 46265652.

256562640 is a `hidden beast` number, since 2 + 5 + 6 + 5 + 6 + 2 + 640 = 666.

It can be written as a sum of positive squares in 6 ways, for example, as 18045504 + 238517136 = 4248^2 + 15444^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 256562595 and 256562604.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 1872652 + ... + 1872788.

Almost surely, 2^256562640 is an apocalyptic number.

256562640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 256562640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (476744598).

256562640 is an abundant number, since it is smaller than the sum of its proper divisors (696926556).

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

256562640 is a wasteful number, since it uses less digits than its factorization.

256562640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 196 (or 164 counting only the distinct ones).

The product of its (nonzero) digits is 86400, while the sum is 36.

The square root of 256562640 is about 16017.5728498421. The cubic root of 256562640 is about 635.4252550638.

The spelling of 256562640 in words is "two hundred fifty-six million, five hundred sixty-two thousand, six hundred forty".