231520031 has 2 divisors, whose sum is σ = 231520032. Its totient is φ = 231520030.

The previous prime is 231520027. The next prime is 231520039. The reversal of 231520031 is 130025132.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 231520031 - 2² = 231520027 is a prime.

It is a super-2 number, since 2×231520031² = 107203049508481922, which contains 22 as substring.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 231519991 and 231520009.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (231520039) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 115760015 + 115760016.

It is an arithmetic number, because the mean of its divisors is an integer number (115760016).

Almost surely, 2^231520031 is an apocalyptic number.

231520031 is a deficient number, since it is larger than the sum of its proper divisors (1).

231520031 is an equidigital number, since it uses as much as digits as its factorization.

231520031 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 180, while the sum is 17.

The square root of 231520031 is about 15215.7822999674. The cubic root of 231520031 is about 614.0393321152.

Adding to 231520031 its reverse (130025132), we get a palindrome (361545163).

The spelling of 231520031 in words is "two hundred thirty-one million, five hundred twenty thousand, thirty-one".