21172563036 has 36 divisors (see below), whose sum is σ = 53529453432. Its totient is φ = 7056213024.

The previous prime is 21172563031. The next prime is 21172563073. The reversal of 21172563036 is 63036527112.

21172563036 is a `hidden beast` number, since 2 + 1 + 17 + 2 + 5 + 630 + 3 + 6 = 666.

It is a tau number, because it is divible by the number of its divisors (36).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21172563031) 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, 153295 + ... + 256601.

It is an arithmetic number, because the mean of its divisors is an integer number (1486929262).

Almost surely, 2^21172563036 is an apocalyptic number.

It is an amenable number.

21172563036 is an abundant number, since it is smaller than the sum of its proper divisors (32356890396).

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

21172563036 is a wasteful number, since it uses less digits than its factorization.

21172563036 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 109010 (or 109005 counting only the distinct ones).

The product of its (nonzero) digits is 45360, while the sum is 36.

The spelling of 21172563036 in words is "twenty-one billion, one hundred seventy-two million, five hundred sixty-three thousand, thirty-six".