31131977 has 2 divisors, whose sum is σ = 31131978. Its totient is φ = 31131976.

The previous prime is 31131959. The next prime is 31131979. The reversal of 31131977 is 77913113.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20757136 + 10374841 = 4556^2 + 3221^2 .

It is a cyclic number.

It is not a de Polignac number, because 31131977 - 2⁸ = 31131721 is a prime.

Together with 31131979, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (31131979) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15565988 + 15565989.

It is an arithmetic number, because the mean of its divisors is an integer number (15565989).

Almost surely, 2^31131977 is an apocalyptic number.

It is an amenable number.

31131977 is a deficient number, since it is larger than the sum of its proper divisors (1).

31131977 is an equidigital number, since it uses as much as digits as its factorization.

31131977 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3969, while the sum is 32.

The square root of 31131977 is about 5579.6036597594. The cubic root of 31131977 is about 314.5832297920.

The spelling of 31131977 in words is "thirty-one million, one hundred thirty-one thousand, nine hundred seventy-seven".