31399999 has 2 divisors, whose sum is σ = 31400000. Its totient is φ = 31399998.

The previous prime is 31399981. The next prime is 31400021. The reversal of 31399999 is 99999313.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 31399999 - 2⁷ = 31399871 is a prime.

31399999 is a modest number, since divided by 9999 gives 3139 as remainder.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31399499) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15699999 + 15700000.

It is an arithmetic number, because the mean of its divisors is an integer number (15700000).

Almost surely, 2^31399999 is an apocalyptic number.

31399999 is a deficient number, since it is larger than the sum of its proper divisors (1).

31399999 is an equidigital number, since it uses as much as digits as its factorization.

31399999 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 531441, while the sum is 52.

The square root of 31399999 is about 5603.5702012199. The cubic root of 31399999 is about 315.4834233385.

The spelling of 31399999 in words is "thirty-one million, three hundred ninety-nine thousand, nine hundred ninety-nine".