31372139 has 2 divisors, whose sum is σ = 31372140. Its totient is φ = 31372138.

The previous prime is 31372111. The next prime is 31372141. The reversal of 31372139 is 93127313.

It is a strong prime.

It is an emirp because it is prime and its reverse (93127313) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31372139 is a prime.

It is a super-2 number, since 2×31372139² = 1968422210870642, which contains 22 as substring.

Together with 31372141, 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 (31371139) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15686069 + 15686070.

It is an arithmetic number, because the mean of its divisors is an integer number (15686070).

Almost surely, 2^31372139 is an apocalyptic number.

31372139 is a deficient number, since it is larger than the sum of its proper divisors (1).

31372139 is an equidigital number, since it uses as much as digits as its factorization.

31372139 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3402, while the sum is 29.

The square root of 31372139 is about 5601.0837344214. The cubic root of 31372139 is about 315.3900903319.

The spelling of 31372139 in words is "thirty-one million, three hundred seventy-two thousand, one hundred thirty-nine".