31320213156 has 36 divisors (see below), whose sum is σ = 80352194832. Its totient is φ = 10284248304.

The previous prime is 31320213097. The next prime is 31320213157. The reversal of 31320213156 is 65131202313.

31320213156 is a `hidden beast` number, since 3 + 1 + 320 + 21 + 315 + 6 = 666.

It is a tau number, because it is divible by the number of its divisors (36).

It is not an unprimeable number, because it can be changed into a prime (31320213157) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6490170 + ... + 6494993.

It is an arithmetic number, because the mean of its divisors is an integer number (2232005412).

Almost surely, 2^31320213156 is an apocalyptic number.

31320213156 is a gapful number since it is divisible by the number (36) formed by its first and last digit.

It is an amenable number.

31320213156 is an abundant number, since it is smaller than the sum of its proper divisors (49031981676).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

31320213156 is a wasteful number, since it uses less digits than its factorization.

31320213156 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12985240 (or 12985235 counting only the distinct ones).

The product of its (nonzero) digits is 3240, while the sum is 27.

Adding to 31320213156 its reverse (65131202313), we get a palindrome (96451415469).

The spelling of 31320213156 in words is "thirty-one billion, three hundred twenty million, two hundred thirteen thousand, one hundred fifty-six".