231475991 has 2 divisors, whose sum is σ = 231475992. Its totient is φ = 231475990.

The previous prime is 231475973. The next prime is 231476053. The reversal of 231475991 is 199574132.

231475991 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-231475991 is a prime.

It is a super-2 number, since 2×231475991² = 107162268818864162, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (231475291) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 115737995 + 115737996.

It is an arithmetic number, because the mean of its divisors is an integer number (115737996).

Almost surely, 2^231475991 is an apocalyptic number.

231475991 is a deficient number, since it is larger than the sum of its proper divisors (1).

231475991 is an equidigital number, since it uses as much as digits as its factorization.

231475991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 68040, while the sum is 41.

The square root of 231475991 is about 15214.3350495511. The cubic root of 231475991 is about 614.0003952294. Note that the first 3 decimals are identical.

The spelling of 231475991 in words is "two hundred thirty-one million, four hundred seventy-five thousand, nine hundred ninety-one".