231505131 has 16 divisors (see below), whose sum is σ = 362638080. Its totient is φ = 129513120.

The previous prime is 231505123. The next prime is 231505159. The reversal of 231505131 is 131505132.

It is not a de Polignac number, because 231505131 - 2³ = 231505123 is a prime.

It is a super-2 number, since 2×231505131² = 107189251358654322, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 231505098 and 231505107.

It is not an unprimeable number, because it can be changed into a prime (231505111) 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, 269391 + ... + 270248.

It is an arithmetic number, because the mean of its divisors is an integer number (22664880).

Almost surely, 2^231505131 is an apocalyptic number.

231505131 is a deficient number, since it is larger than the sum of its proper divisors (131132949).

231505131 is a wasteful number, since it uses less digits than its factorization.

231505131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 539666.

The product of its (nonzero) digits is 450, while the sum is 21.

The square root of 231505131 is about 15215.2926688907. The cubic root of 231505131 is about 614.0261591984.

Subtracting from 231505131 its reverse (131505132), we obtain a palindrome (99999999).

The spelling of 231505131 in words is "two hundred thirty-one million, five hundred five thousand, one hundred thirty-one".