31399693 has 6 divisors (see below), whose sum is σ = 34001034. Its totient is φ = 28984176.

The previous prime is 31399661. The next prime is 31399729. The reversal of 31399693 is 39699313.

It can be written as a sum of positive squares in 3 ways, for example, as 4338889 + 27060804 = 2083^2 + 5202^2 .

It is not a de Polignac number, because 31399693 - 2⁵ = 31399661 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31319693) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 92730 + ... + 93067.

It is an arithmetic number, because the mean of its divisors is an integer number (5666839).

Almost surely, 2^31399693 is an apocalyptic number.

It is an amenable number.

31399693 is a deficient number, since it is larger than the sum of its proper divisors (2601341).

31399693 is a wasteful number, since it uses less digits than its factorization.

31399693 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 185823 (or 185810 counting only the distinct ones).

The product of its digits is 118098, while the sum is 43.

The square root of 31399693 is about 5603.5428971321. The cubic root of 31399693 is about 315.4823985164.

The spelling of 31399693 in words is "thirty-one million, three hundred ninety-nine thousand, six hundred ninety-three".