31213965 has 16 divisors (see below), whose sum is σ = 50276736. Its totient is φ = 16536000.

The previous prime is 31213961. The next prime is 31213981. The reversal of 31213965 is 56931213.

It is not a de Polignac number, because 31213965 - 2² = 31213961 is a prime.

It is a super-2 number, since 2×31213965² = 1948623222042450, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31213961) 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 15 ways as a sum of consecutive naturals, for example, 4626 + ... + 9155.

It is an arithmetic number, because the mean of its divisors is an integer number (3142296).

Almost surely, 2^31213965 is an apocalyptic number.

It is an amenable number.

31213965 is a deficient number, since it is larger than the sum of its proper divisors (19062771).

31213965 is a wasteful number, since it uses less digits than its factorization.

31213965 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13940.

The product of its digits is 4860, while the sum is 30.

The square root of 31213965 is about 5586.9459456845. The cubic root of 31213965 is about 314.8591458944.

The spelling of 31213965 in words is "thirty-one million, two hundred thirteen thousand, nine hundred sixty-five".