31199999 has 2 divisors, whose sum is σ = 31200000. Its totient is φ = 31199998.

The previous prime is 31199941. The next prime is 31200007. The reversal of 31199999 is 99999113.

It is a strong prime.

It is an emirp because it is prime and its reverse (99999113) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31199999 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

31199999 is a modest number, since divided by 9999 gives 3119 as remainder.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31199939) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15599999 + 15600000.

It is an arithmetic number, because the mean of its divisors is an integer number (15600000).

Almost surely, 2^31199999 is an apocalyptic number.

31199999 is a deficient number, since it is larger than the sum of its proper divisors (1).

31199999 is an equidigital number, since it uses as much as digits as its factorization.

31199999 is an evil number, because the sum of its binary digits is even.

The product of its digits is 177147, while the sum is 50.

The square root of 31199999 is about 5585.6959279932. The cubic root of 31199999 is about 314.8121799629.

The spelling of 31199999 in words is "thirty-one million, one hundred ninety-nine thousand, nine hundred ninety-nine".