21172505662 has 16 divisors (see below), whose sum is σ = 39595335552. Its totient is φ = 8249028120.

The previous prime is 21172505647. The next prime is 21172505663. The reversal of 21172505662 is 26650527112.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21172505663) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 68741748 + ... + 68742055.

It is an arithmetic number, because the mean of its divisors is an integer number (2474708472).

Almost surely, 2^21172505662 is an apocalyptic number.

21172505662 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

21172505662 is a deficient number, since it is larger than the sum of its proper divisors (18422829890).

21172505662 is a wasteful number, since it uses less digits than its factorization.

21172505662 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 137483823.

The product of its (nonzero) digits is 50400, while the sum is 37.

The spelling of 21172505662 in words is "twenty-one billion, one hundred seventy-two million, five hundred five thousand, six hundred sixty-two".