31518321156 has 135 divisors (see below), whose sum is σ = 95915454789. Its totient is φ = 8998843392.

The previous prime is 31518321137. The next prime is 31518321157. The reversal of 31518321156 is 65112381513.

It is a happy number.

The square root of 31518321156 is 177534.

It is a perfect power (a square), and thus also a powerful number.

31518321156 is a `hidden beast` number, since 315 + 1 + 8 + 321 + 15 + 6 = 666.

It can be written as a sum of positive squares in only one way, i.e., 401361156 + 31116960000 = 20034^2 + 176400^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 31518321156.

It is not an unprimeable number, because it can be changed into a prime (31518321157) by changing a digit.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 22368580 + ... + 22369988.

Almost surely, 2^31518321156 is an apocalyptic number.

31518321156 is a gapful number since it is divisible by the number (36) formed by its first and last digit.

31518321156 is the 177534-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31518321156

31518321156 is an abundant number, since it is smaller than the sum of its proper divisors (64397133633).

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

31518321156 is an equidigital number, since it uses as much as digits as its factorization.

31518321156 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2848 (or 1421 counting only the distinct ones).

The product of its digits is 21600, while the sum is 36.

Multiplying 31518321156 by its sum of digits (36), we get a square (1134659561616 = 1065204²).

31518321156 divided by its sum of digits (36) gives a square (875508921 = 29589²).

The spelling of 31518321156 in words is "thirty-one billion, five hundred eighteen million, three hundred twenty-one thousand, one hundred fifty-six".