31102121220 has 144 divisors (see below), whose sum is σ = 92978323200. Its totient is φ = 7764128768.

The previous prime is 31102121213. The next prime is 31102121251. The reversal of 31102121220 is 2212120113.

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

It is a self number, because there is not a number n which added to its sum of digits gives 31102121220.

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, 1481356 + ... + 1502204.

It is an arithmetic number, because the mean of its divisors is an integer number (645682800).

Almost surely, 2^31102121220 is an apocalyptic number.

31102121220 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 31102121220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (46489161600).

31102121220 is an abundant number, since it is smaller than the sum of its proper divisors (61876201980).

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

31102121220 is a wasteful number, since it uses less digits than its factorization.

31102121220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20954 (or 20929 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 15.

Adding to 31102121220 its reverse (2212120113), we get a palindrome (33314241333).

The spelling of 31102121220 in words is "thirty-one billion, one hundred two million, one hundred twenty-one thousand, two hundred twenty".