31121102320 has 160 divisors (see below), whose sum is σ = 91299156480. Its totient is φ = 9583057920.

The previous prime is 31121102303. The next prime is 31121102371. The reversal of 31121102320 is 2320112113.

It is a super-2 number, since 2×31121102320² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (16).

It is a junction number, because it is equal to n+sod(n) for n = 31121102294 and 31121102303.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 480846 + ... + 541714.

It is an arithmetic number, because the mean of its divisors is an integer number (570619728).

Almost surely, 2^31121102320 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31121102320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45649578240).

31121102320 is an abundant number, since it is smaller than the sum of its proper divisors (60178054160).

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

31121102320 is a wasteful number, since it uses less digits than its factorization.

31121102320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60983 (or 60977 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 16.

Adding to 31121102320 its reverse (2320112113), we get a palindrome (33441214433).

The spelling of 31121102320 in words is "thirty-one billion, one hundred twenty-one million, one hundred two thousand, three hundred twenty".