31213121022 has 48 divisors (see below), whose sum is σ = 70114065840. Its totient is φ = 10023543936.

The previous prime is 31213121021. The next prime is 31213121029. The reversal of 31213121022 is 22012131213.

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 = 31213120986 and 31213121004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31213121021) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 173133 + ... + 303975.

It is an arithmetic number, because the mean of its divisors is an integer number (1460709705).

Almost surely, 2^31213121022 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31213121022, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35057032920).

31213121022 is an abundant number, since it is smaller than the sum of its proper divisors (38900944818).

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

31213121022 is a wasteful number, since it uses less digits than its factorization.

31213121022 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 131337 (or 131334 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

Adding to 31213121022 its reverse (22012131213), we get a palindrome (53225252235).

The spelling of 31213121022 in words is "thirty-one billion, two hundred thirteen million, one hundred twenty-one thousand, twenty-two".