31213133220 has 192 divisors, whose sum is σ = 94222227456. Its totient is φ = 7692072960.

The previous prime is 31213133209. The next prime is 31213133221. The reversal of 31213133220 is 2233131213.

It is not an unprimeable number, because it can be changed into a prime (31213133221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 30274105 + ... + 30275135.

It is an arithmetic number, because the mean of its divisors is an integer number (490740768).

Almost surely, 2^31213133220 is an apocalyptic number.

31213133220 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 31213133220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (47111113728).

31213133220 is an abundant number, since it is smaller than the sum of its proper divisors (63009094236).

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

31213133220 is a wasteful number, since it uses less digits than its factorization.

31213133220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1570 (or 1568 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 21.

Adding to 31213133220 its reverse (2233131213), we get a palindrome (33446264433).

The spelling of 31213133220 in words is "thirty-one billion, two hundred thirteen million, one hundred thirty-three thousand, two hundred twenty".