31893921 has 12 divisors (see below), whose sum is σ = 48779172. Its totient is φ = 20011776.

The previous prime is 31893907. The next prime is 31893937. The reversal of 31893921 is 12939813.

It can be written as a sum of positive squares in 2 ways, for example, as 13950225 + 17943696 = 3735^2 + 4236^2 .

It is not a de Polignac number, because 31893921 - 2⁶ = 31893857 is a prime.

It is not an unprimeable number, because it can be changed into a prime (31893971) 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 11 ways as a sum of consecutive naturals, for example, 104076 + ... + 104381.

It is an arithmetic number, because the mean of its divisors is an integer number (4064931).

Almost surely, 2^31893921 is an apocalyptic number.

It is an amenable number.

31893921 is a deficient number, since it is larger than the sum of its proper divisors (16885251).

31893921 is a wasteful number, since it uses less digits than its factorization.

31893921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 208480 (or 208477 counting only the distinct ones).

The product of its digits is 11664, while the sum is 36.

The square root of 31893921 is about 5647.4703186471. The cubic root of 31893921 is about 317.1290097088.

The spelling of 31893921 in words is "thirty-one million, eight hundred ninety-three thousand, nine hundred twenty-one".