31320861 has 16 divisors (see below), whose sum is σ = 49062720. Its totient is φ = 17521920.

The previous prime is 31320853. The next prime is 31320889. The reversal of 31320861 is 16802313.

It is not a de Polignac number, because 31320861 - 2³ = 31320853 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31320061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 36076 + ... + 36933.

It is an arithmetic number, because the mean of its divisors is an integer number (3066420).

Almost surely, 2^31320861 is an apocalyptic number.

It is an amenable number.

31320861 is a deficient number, since it is larger than the sum of its proper divisors (17741859).

31320861 is a wasteful number, since it uses less digits than its factorization.

31320861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73036.

The product of its (nonzero) digits is 864, while the sum is 24.

The square root of 31320861 is about 5596.5043553990. The cubic root of 31320861 is about 315.2181607900.

The spelling of 31320861 in words is "thirty-one million, three hundred twenty thousand, eight hundred sixty-one".