21177165231 has 16 divisors (see below), whose sum is σ = 31841843200. Its totient is φ = 13907390904.

The previous prime is 21177165221. The next prime is 21177165239. The reversal of 21177165231 is 13256177112.

21177165231 is a `hidden beast` number, since 2 + 117 + 7 + 16 + 523 + 1 = 666.

It is not a de Polignac number, because 21177165231 - 2⁶ = 21177165167 is a prime.

It is a super-2 number, since 2×21177165231² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21177165239) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5851471 + ... + 5855088.

It is an arithmetic number, because the mean of its divisors is an integer number (1990115200).

Almost surely, 2^21177165231 is an apocalyptic number.

21177165231 is a deficient number, since it is larger than the sum of its proper divisors (10664677969).

21177165231 is a wasteful number, since it uses less digits than its factorization.

21177165231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11706635 (or 11706629 counting only the distinct ones).

The product of its digits is 17640, while the sum is 36.

The spelling of 21177165231 in words is "twenty-one billion, one hundred seventy-seven million, one hundred sixty-five thousand, two hundred thirty-one".