31136331220 has 24 divisors (see below), whose sum is σ = 65389653000. Its totient is φ = 12453892992.

The previous prime is 31136331209. The next prime is 31136331229. The reversal of 31136331220 is 2213363113.

It can be written as a sum of positive squares in 4 ways, for example, as 6871415236 + 24264915984 = 82894^2 + 155772^2 .

It is a super-2 number, since 2×31136331220² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31136331229) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 648606 + ... + 694954.

It is an arithmetic number, because the mean of its divisors is an integer number (2724568875).

Almost surely, 2^31136331220 is an apocalyptic number.

It is an amenable number.

31136331220 is an abundant number, since it is smaller than the sum of its proper divisors (34253321780).

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

31136331220 is a wasteful number, since it uses less digits than its factorization.

31136331220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79947 (or 79945 counting only the distinct ones).

The product of its (nonzero) digits is 1944, while the sum is 25.

Adding to 31136331220 its reverse (2213363113), we get a palindrome (33349694333).

The spelling of 31136331220 in words is "thirty-one billion, one hundred thirty-six million, three hundred thirty-one thousand, two hundred twenty".