31031112121020 has 144 divisors (see below), whose sum is σ = 102746306688480. Its totient is φ = 7518185740800.

The previous prime is 31031112121007. The next prime is 31031112121049. The reversal of 31031112121020 is 2012121113013.

31031112121020 is a `hidden beast` number, since 3 + 1 + 0 + 311 + 121 + 210 + 20 = 666.

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 = 31031112120984 and 31031112121002.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1390491 + ... + 7999730.

It is an arithmetic number, because the mean of its divisors is an integer number (713516018670).

Almost surely, 2^{31031112121020} is an apocalyptic number.

31031112121020 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31031112121020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (51373153344240).

31031112121020 is an abundant number, since it is smaller than the sum of its proper divisors (71715194567460).

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

31031112121020 is a wasteful number, since it uses less digits than its factorization.

31031112121020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9391916 (or 9391911 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 18.

Adding to 31031112121020 its reverse (2012121113013), we get a palindrome (33043233234033).

The spelling of 31031112121020 in words is "thirty-one trillion, thirty-one billion, one hundred twelve million, one hundred twenty-one thousand, twenty".