31639993 has 16 divisors (see below), whose sum is σ = 40196736. Its totient is φ = 24186240.

The previous prime is 31639969. The next prime is 31639999. The reversal of 31639993 is 39993613.

It is a cyclic number.

It is not a de Polignac number, because 31639993 - 2⁵ = 31639961 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31639999) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 205 + ... + 7957.

It is an arithmetic number, because the mean of its divisors is an integer number (2512296).

Almost surely, 2^31639993 is an apocalyptic number.

It is an amenable number.

31639993 is a deficient number, since it is larger than the sum of its proper divisors (8556743).

31639993 is a wasteful number, since it uses less digits than its factorization.

31639993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7824.

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

The square root of 31639993 is about 5624.9438219417. The cubic root of 31639993 is about 316.2851435998.

The spelling of 31639993 in words is "thirty-one million, six hundred thirty-nine thousand, nine hundred ninety-three".