31899993 has 8 divisors (see below), whose sum is σ = 44772000. Its totient is φ = 20147328.

The previous prime is 31899979. The next prime is 31899997. The reversal of 31899993 is 39999813.

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

It is not a de Polignac number, because 31899993 - 2⁴ = 31899977 is a prime.

It is a Smith number, since the sum of its digits (51) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (31899997) 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, 279768 + ... + 279881.

It is an arithmetic number, because the mean of its divisors is an integer number (5596500).

Almost surely, 2^31899993 is an apocalyptic number.

It is an amenable number.

31899993 is a deficient number, since it is larger than the sum of its proper divisors (12872007).

31899993 is a wasteful number, since it uses less digits than its factorization.

31899993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 559671.

The product of its digits is 472392, while the sum is 51.

The square root of 31899993 is about 5648.0078788897. The cubic root of 31899993 is about 317.1491335558.

The spelling of 31899993 in words is "thirty-one million, eight hundred ninety-nine thousand, nine hundred ninety-three".