231395257 has 2 divisors, whose sum is σ = 231395258. Its totient is φ = 231395256.

The previous prime is 231395237. The next prime is 231395261. The reversal of 231395257 is 752593132.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 231374521 + 20736 = 15211^2 + 144^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-231395257 is a prime.

It is not a weakly prime, because it can be changed into another prime (231395207) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 115697628 + 115697629.

It is an arithmetic number, because the mean of its divisors is an integer number (115697629).

Almost surely, 2^231395257 is an apocalyptic number.

It is an amenable number.

231395257 is a deficient number, since it is larger than the sum of its proper divisors (1).

231395257 is an equidigital number, since it uses as much as digits as its factorization.

231395257 is an evil number, because the sum of its binary digits is even.

The product of its digits is 56700, while the sum is 37.

The square root of 231395257 is about 15211.6815967203. The cubic root of 231395257 is about 613.9290034162.

The spelling of 231395257 in words is "two hundred thirty-one million, three hundred ninety-five thousand, two hundred fifty-seven".