31123320120 has 320 divisors, whose sum is σ = 110733004800. Its totient is φ = 7818612480.

The previous prime is 31123320119. The next prime is 31123320133. The reversal of 31123320120 is 2102332113.

31123320120 is a `hidden beast` number, since 311 + 2 + 332 + 0 + 1 + 20 = 666.

It is a super-2 number, since 2×31123320120² (a number of 22 digits) contains 22 as substring.

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 = 31123320093 and 31123320102.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 11756637 + ... + 11759283.

It is an arithmetic number, because the mean of its divisors is an integer number (346040640).

Almost surely, 2^31123320120 is an apocalyptic number.

31123320120 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 31123320120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (55366502400).

31123320120 is an abundant number, since it is smaller than the sum of its proper divisors (79609684680).

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

31123320120 is a wasteful number, since it uses less digits than its factorization.

31123320120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2880 (or 2867 counting only the distinct ones).

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

Adding to 31123320120 its reverse (2102332113), we get a palindrome (33225652233).

The spelling of 31123320120 in words is "thirty-one billion, one hundred twenty-three million, three hundred twenty thousand, one hundred twenty".