31131979 has 2 divisors, whose sum is σ = 31131980. Its totient is φ = 31131978.

The previous prime is 31131977. The next prime is 31132027. The reversal of 31131979 is 97913113.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 31131979 - 2¹ = 31131977 is a prime.

Together with 31131977, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (31131977) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15565989 + 15565990.

It is an arithmetic number, because the mean of its divisors is an integer number (15565990).

Almost surely, 2^31131979 is an apocalyptic number.

31131979 is a deficient number, since it is larger than the sum of its proper divisors (1).

31131979 is an equidigital number, since it uses as much as digits as its factorization.

31131979 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5103, while the sum is 34.

The square root of 31131979 is about 5579.6038389836. The cubic root of 31131979 is about 314.5832365286.

The spelling of 31131979 in words is "thirty-one million, one hundred thirty-one thousand, nine hundred seventy-nine".