31243139 has 2 divisors, whose sum is σ = 31243140. Its totient is φ = 31243138.

The previous prime is 31243123. The next prime is 31243141. The reversal of 31243139 is 93134213.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 31243139 - 2⁴ = 31243123 is a prime.

It is a super-2 number, since 2×31243139² = 1952267469146642, which contains 22 as substring.

Together with 31243141, 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 (31243439) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15621569 + 15621570.

It is an arithmetic number, because the mean of its divisors is an integer number (15621570).

Almost surely, 2^31243139 is an apocalyptic number.

31243139 is a deficient number, since it is larger than the sum of its proper divisors (1).

31243139 is an equidigital number, since it uses as much as digits as its factorization.

31243139 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1944, while the sum is 26.

The square root of 31243139 is about 5589.5562435671. The cubic root of 31243139 is about 314.9572092710.

The spelling of 31243139 in words is "thirty-one million, two hundred forty-three thousand, one hundred thirty-nine".