31125431 has 2 divisors, whose sum is σ = 31125432. Its totient is φ = 31125430.

The previous prime is 31125427. The next prime is 31125443. The reversal of 31125431 is 13452113.

It is a weak prime.

It is an emirp because it is prime and its reverse (13452113) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31125431 - 2² = 31125427 is a prime.

It is a super-2 number, since 2×31125431² = 1937584909871522, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31125461) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15562715 + 15562716.

It is an arithmetic number, because the mean of its divisors is an integer number (15562716).

Almost surely, 2^31125431 is an apocalyptic number.

31125431 is a deficient number, since it is larger than the sum of its proper divisors (1).

31125431 is an equidigital number, since it uses as much as digits as its factorization.

31125431 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 360, while the sum is 20.

The square root of 31125431 is about 5579.0170281153. The cubic root of 31125431 is about 314.5611795148.

Adding to 31125431 its reverse (13452113), we get a palindrome (44577544).

The spelling of 31125431 in words is "thirty-one million, one hundred twenty-five thousand, four hundred thirty-one".