20256640556 has 24 divisors (see below), whose sum is σ = 35615023584. Its totient is φ = 10081008000.

The previous prime is 20256640549. The next prime is 20256640559. The reversal of 20256640556 is 65504665202.

It is a super-2 number, since 2×20256640556² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20256640559) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 954056 + ... + 975056.

It is an arithmetic number, because the mean of its divisors is an integer number (1483959316).

Almost surely, 2^20256640556 is an apocalyptic number.

It is an amenable number.

20256640556 is a deficient number, since it is larger than the sum of its proper divisors (15358383028).

20256640556 is a wasteful number, since it uses less digits than its factorization.

20256640556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22121 (or 22119 counting only the distinct ones).

The product of its (nonzero) digits is 432000, while the sum is 41.

The spelling of 20256640556 in words is "twenty billion, two hundred fifty-six million, six hundred forty thousand, five hundred fifty-six".