31322881 has 4 divisors (see below), whose sum is σ = 31378500. Its totient is φ = 31267264.

The previous prime is 31322869. The next prime is 31322909. The reversal of 31322881 is 18822313.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 17514225 + 13808656 = 4185^2 + 3716^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31322881 is a prime.

It is a super-2 number, since 2×31322881² = 1962245748280322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31322981) 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, 26956 + ... + 28093.

It is an arithmetic number, because the mean of its divisors is an integer number (7844625).

Almost surely, 2^31322881 is an apocalyptic number.

It is an amenable number.

31322881 is a deficient number, since it is larger than the sum of its proper divisors (55619).

31322881 is an equidigital number, since it uses as much as digits as its factorization.

31322881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55618.

The product of its digits is 2304, while the sum is 28.

The square root of 31322881 is about 5596.6848222854. The cubic root of 31322881 is about 315.2249371788.

The spelling of 31322881 in words is "thirty-one million, three hundred twenty-two thousand, eight hundred eighty-one".