31131230220 has 36 divisors (see below), whose sum is σ = 94431398880. Its totient is φ = 8301661344.

The previous prime is 31131230191. The next prime is 31131230243. The reversal of 31131230220 is 2203213113.

31131230220 is a `hidden beast` number, since 31 + 1 + 312 + 302 + 20 = 666.

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

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 31131230193 and 31131230202.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 86475460 + ... + 86475819.

Almost surely, 2^31131230220 is an apocalyptic number.

31131230220 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

31131230220 is an abundant number, since it is smaller than the sum of its proper divisors (63300168660).

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

31131230220 is a wasteful number, since it uses less digits than its factorization.

31131230220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 172951294 (or 172951289 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 18.

Adding to 31131230220 its reverse (2203213113), we get a palindrome (33334443333).

The spelling of 31131230220 in words is "thirty-one billion, one hundred thirty-one million, two hundred thirty thousand, two hundred twenty".