31312021020 has 96 divisors (see below), whose sum is σ = 101841148416. Its totient is φ = 7039699200.

The previous prime is 31312020967. The next prime is 31312021049. The reversal of 31312021020 is 2012021313.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 585466 + ... + 636705.

It is an arithmetic number, because the mean of its divisors is an integer number (1060845296).

Almost surely, 2^31312021020 is an apocalyptic number.

31312021020 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

31312021020 is an abundant number, since it is smaller than the sum of its proper divisors (70529127396).

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

31312021020 is a wasteful number, since it uses less digits than its factorization.

31312021020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1222251 (or 1222249 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 15.

Adding to 31312021020 its reverse (2012021313), we get a palindrome (33324042333).

The spelling of 31312021020 in words is "thirty-one billion, three hundred twelve million, twenty-one thousand, twenty".