256536636040 has 128 divisors (see below), whose sum is σ = 594795104640. Its totient is φ = 99524468736.

The previous prime is 256536636029. The next prime is 256536636077. The reversal of 256536636040 is 40636635652.

It is a super-2 number, since 2×256536636040² (a number of 24 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 171825534 + ... + 171827026.

It is an arithmetic number, because the mean of its divisors is an integer number (4646836755).

Almost surely, 2^256536636040 is an apocalyptic number.

256536636040 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 256536636040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (297397552320).

256536636040 is an abundant number, since it is smaller than the sum of its proper divisors (338258468600).

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

256536636040 is a wasteful number, since it uses less digits than its factorization.

256536636040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2183 (or 2179 counting only the distinct ones).

The product of its (nonzero) digits is 2332800, while the sum is 46.

The spelling of 256536636040 in words is "two hundred fifty-six billion, five hundred thirty-six million, six hundred thirty-six thousand, forty".