31399979 has 8 divisors (see below), whose sum is σ = 34223952. Its totient is φ = 28634400.

The previous prime is 31399897. The next prime is 31399981. The reversal of 31399979 is 97999313.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 31399979 - 2¹² = 31395883 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31399999) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13472 + ... + 15629.

It is an arithmetic number, because the mean of its divisors is an integer number (4277994).

Almost surely, 2^31399979 is an apocalyptic number.

31399979 is a deficient number, since it is larger than the sum of its proper divisors (2823973).

31399979 is a wasteful number, since it uses less digits than its factorization.

31399979 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29197.

The product of its digits is 413343, while the sum is 50.

The square root of 31399979 is about 5603.5684166431. The cubic root of 31399979 is about 315.4833563569.

The spelling of 31399979 in words is "thirty-one million, three hundred ninety-nine thousand, nine hundred seventy-nine".