31139929 has 2 divisors, whose sum is σ = 31139930. Its totient is φ = 31139928.

The previous prime is 31139893. The next prime is 31139947. The reversal of 31139929 is 92993113.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 23299929 + 7840000 = 4827^2 + 2800^2 .

It is a cyclic number.

It is not a de Polignac number, because 31139929 - 2¹¹ = 31137881 is a prime.

It is not a weakly prime, because it can be changed into another prime (31139959) 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, 15569964 + 15569965.

It is an arithmetic number, because the mean of its divisors is an integer number (15569965).

Almost surely, 2^31139929 is an apocalyptic number.

It is an amenable number.

31139929 is a deficient number, since it is larger than the sum of its proper divisors (1).

31139929 is an equidigital number, since it uses as much as digits as its factorization.

31139929 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13122, while the sum is 37.

The square root of 31139929 is about 5580.3162096784. The cubic root of 31139929 is about 314.6100120389.

The spelling of 31139929 in words is "thirty-one million, one hundred thirty-nine thousand, nine hundred twenty-nine".