231021220131 has 48 divisors (see below), whose sum is σ = 361877152000. Its totient is φ = 141176825856.

The previous prime is 231021220127. The next prime is 231021220139. The reversal of 231021220131 is 131022120132.

231021220131 is a `hidden beast` number, since 2 + 310 + 2 + 1 + 220 + 131 = 666.

It is not a de Polignac number, because 231021220131 - 2² = 231021220127 is a prime.

It is a super-2 number, since 2×231021220131² (a number of 24 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (231021220139) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 10660395 + ... + 10682043.

Almost surely, 2^231021220131 is an apocalyptic number.

231021220131 is a deficient number, since it is larger than the sum of its proper divisors (130855931869).

231021220131 is a wasteful number, since it uses less digits than its factorization.

231021220131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22300 (or 22297 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

Adding to 231021220131 its reverse (131022120132), we get a palindrome (362043340263).

Subtracting from 231021220131 its reverse (131022120132), we obtain a palindrome (99999099999).

The spelling of 231021220131 in words is "two hundred thirty-one billion, twenty-one million, two hundred twenty thousand, one hundred thirty-one".