231397681 has 2 divisors, whose sum is σ = 231397682. Its totient is φ = 231397680.

The previous prime is 231397679. The next prime is 231397697. The reversal of 231397681 is 186793132.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 217267600 + 14130081 = 14740^2 + 3759^2 .

It is a cyclic number.

It is not a de Polignac number, because 231397681 - 2¹ = 231397679 is a prime.

It is a super-2 number, since 2×231397681² = 107089773544355522, which contains 22 as substring.

Together with 231397679, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (231397601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 115698840 + 115698841.

It is an arithmetic number, because the mean of its divisors is an integer number (115698841).

Almost surely, 2^231397681 is an apocalyptic number.

It is an amenable number.

231397681 is a deficient number, since it is larger than the sum of its proper divisors (1).

231397681 is an equidigital number, since it uses as much as digits as its factorization.

231397681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 54432, while the sum is 40.

The square root of 231397681 is about 15211.7612721210. The cubic root of 231397681 is about 613.9311471633.

The spelling of 231397681 in words is "two hundred thirty-one million, three hundred ninety-seven thousand, six hundred eighty-one".