21636460008 has 24 divisors (see below), whose sum is σ = 58598746050. Its totient is φ = 7212153312.

The previous prime is 21636459991. The next prime is 21636460037. The reversal of 21636460008 is 80006463612.

21636460008 is a `hidden beast` number, since 2 + 1 + 6 + 3 + 646 + 0 + 0 + 0 + 8 = 666.

It can be written as a sum of positive squares in only one way, i.e., 17657625924 + 3978834084 = 132882^2 + 63078^2 .

It is a tau number, because it is divible by the number of its divisors (24).

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

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 150253123 + ... + 150253266.

Almost surely, 2^21636460008 is an apocalyptic number.

It is an amenable number.

21636460008 is an abundant number, since it is smaller than the sum of its proper divisors (36962286042).

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

21636460008 is a wasteful number, since it uses less digits than its factorization.

21636460008 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 300506401 (or 300506394 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 36.

The spelling of 21636460008 in words is "twenty-one billion, six hundred thirty-six million, four hundred sixty thousand, eight".