31981893 has 4 divisors (see below), whose sum is σ = 42642528. Its totient is φ = 21321260.

The previous prime is 31981889. The next prime is 31981907. The reversal of 31981893 is 39818913.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 31981893 - 2² = 31981889 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31981823) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5330313 + ... + 5330318.

It is an arithmetic number, because the mean of its divisors is an integer number (10660632).

Almost surely, 2^31981893 is an apocalyptic number.

It is an amenable number.

31981893 is a deficient number, since it is larger than the sum of its proper divisors (10660635).

31981893 is a wasteful number, since it uses less digits than its factorization.

31981893 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10660634.

The product of its digits is 46656, while the sum is 42.

The square root of 31981893 is about 5655.2535752166. The cubic root of 31981893 is about 317.4203176980.

The spelling of 31981893 in words is "thirty-one million, nine hundred eighty-one thousand, eight hundred ninety-three".