256005531 has 12 divisors (see below), whose sum is σ = 378386008. Its totient is φ = 166701024.

The previous prime is 256005511. The next prime is 256005539. The reversal of 256005531 is 135500652.

256005531 is a `hidden beast` number, since 2 + 5 + 600 + 5 + 53 + 1 = 666.

It is not a de Polignac number, because 256005531 - 2⁶ = 256005467 is a prime.

It is a super-2 number, since 2×256005531² = 131077663805183922, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 256005495 and 256005504.

It is not an unprimeable number, because it can be changed into a prime (256005539) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 330370 + ... + 331143.

Almost surely, 2^256005531 is an apocalyptic number.

256005531 is a deficient number, since it is larger than the sum of its proper divisors (122380477).

256005531 is a wasteful number, since it uses less digits than its factorization.

256005531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 661562 (or 661559 counting only the distinct ones).

The product of its (nonzero) digits is 4500, while the sum is 27.

The square root of 256005531 is about 16000.1728428164. The cubic root of 256005531 is about 634.9649936269.

The spelling of 256005531 in words is "two hundred fifty-six million, five thousand, five hundred thirty-one".