31499939 has 2 divisors, whose sum is σ = 31499940. Its totient is φ = 31499938.

The previous prime is 31499933. The next prime is 31499989. The reversal of 31499939 is 93999413.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31499939 is a prime.

It is a Sophie Germain prime.

It is a junction number, because it is equal to n+sod(n) for n = 31499893 and 31499902.

It is not a weakly prime, because it can be changed into another prime (31499933) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15749969 + 15749970.

It is an arithmetic number, because the mean of its divisors is an integer number (15749970).

Almost surely, 2^31499939 is an apocalyptic number.

31499939 is a deficient number, since it is larger than the sum of its proper divisors (1).

31499939 is an equidigital number, since it uses as much as digits as its factorization.

31499939 is an evil number, because the sum of its binary digits is even.

The product of its digits is 236196, while the sum is 47.

The square root of 31499939 is about 5612.4806458464. The cubic root of 31499939 is about 315.8177760213.

The spelling of 31499939 in words is "thirty-one million, four hundred ninety-nine thousand, nine hundred thirty-nine".