231639101521 has 27 divisors (see below), whose sum is σ = 248583477051. Its totient is φ = 215817688224.

The previous prime is 231639101513. The next prime is 231639101531. The reversal of 231639101521 is 125101936132.

The square root of 231639101521 is 481289.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 131489638225 + 100149463296 = 362615^2 + 316464^2 .

It is not a de Polignac number, because 231639101521 - 2³ = 231639101513 is a prime.

It is a super-2 number, since 2×231639101521² (a number of 24 digits) contains 22 as substring.

It is a hoax number, since the sum of its digits (34) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (231639101501) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 667547670 + ... + 667548016.

Almost surely, 2^231639101521 is an apocalyptic number.

231639101521 is the 481289-th square number.

231639101521 is the 240645-th centered octagonal number.

It is an amenable number.

231639101521 is a deficient number, since it is larger than the sum of its proper divisors (16944375530).

231639101521 is an frugal number, since it uses more digits than its factorization.

231639101521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 878 (or 439 counting only the distinct ones).

The product of its (nonzero) digits is 9720, while the sum is 34.

The spelling of 231639101521 in words is "two hundred thirty-one billion, six hundred thirty-nine million, one hundred one thousand, five hundred twenty-one".