21172682205072 has 60 divisors (see below), whose sum is σ = 62739639188460. Its totient is φ = 6642410102784.

The previous prime is 21172682205049. The next prime is 21172682205119. The reversal of 21172682205072 is 27050228627112.

21172682205072 is a `hidden beast` number, since 2 + 11 + 72 + 68 + 2 + 2 + 0 + 507 + 2 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 10354082386176 + 10818599818896 = 3217776^2 + 3289164^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4324483297 + ... + 4324488192.

It is an arithmetic number, because the mean of its divisors is an integer number (1045660653141).

Almost surely, 2^{21172682205072} is an apocalyptic number.

It is an amenable number.

21172682205072 is an abundant number, since it is smaller than the sum of its proper divisors (41566956983388).

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

21172682205072 is a wasteful number, since it uses less digits than its factorization.

21172682205072 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8648971520 (or 8648971511 counting only the distinct ones).

The product of its (nonzero) digits is 376320, while the sum is 45.

The spelling of 21172682205072 in words is "twenty-one trillion, one hundred seventy-two billion, six hundred eighty-two million, two hundred five thousand, seventy-two".