21537029975 has 12 divisors (see below), whose sum is σ = 26771225520. Its totient is φ = 17187489600.

The previous prime is 21537029953. The next prime is 21537029977. The reversal of 21537029975 is 57992073512.

It is not a de Polignac number, because 21537029975 - 2³⁰ = 20463288151 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21537029977) 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, 1042931 + ... + 1063380.

It is an arithmetic number, because the mean of its divisors is an integer number (2230935460).

Almost surely, 2^21537029975 is an apocalyptic number.

21537029975 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21537029975 is a deficient number, since it is larger than the sum of its proper divisors (5234195545).

21537029975 is a wasteful number, since it uses less digits than its factorization.

21537029975 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2106730 (or 2106725 counting only the distinct ones).

The product of its (nonzero) digits is 1190700, while the sum is 50.

Adding to 21537029975 its sum of digits (50), we get a square (21537030025 = 146755²).

The spelling of 21537029975 in words is "twenty-one billion, five hundred thirty-seven million, twenty-nine thousand, nine hundred seventy-five".