21156106605218 has 32 divisors (see below), whose sum is σ = 35716763763072. Its totient is φ = 9325248768000.

The previous prime is 21156106605169. The next prime is 21156106605223. The reversal of 21156106605218 is 81250660165112.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 27212708 + ... + 27979343.

It is an arithmetic number, because the mean of its divisors is an integer number (1116148867596).

Almost surely, 2^{21156106605218} is an apocalyptic number.

21156106605218 is a deficient number, since it is larger than the sum of its proper divisors (14560657157854).

21156106605218 is a wasteful number, since it uses less digits than its factorization.

21156106605218 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55192730.

The product of its (nonzero) digits is 172800, while the sum is 44.

The spelling of 21156106605218 in words is "twenty-one trillion, one hundred fifty-six billion, one hundred six million, six hundred five thousand, two hundred eighteen".