31313222220 has 192 divisors, whose sum is σ = 102645043200. Its totient is φ = 6984610560.

The previous prime is 31313222209. The next prime is 31313222243. The reversal of 31313222220 is 2222231313.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 3439875 + ... + 3448965.

It is an arithmetic number, because the mean of its divisors is an integer number (534609600).

Almost surely, 2^31313222220 is an apocalyptic number.

31313222220 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 31313222220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (51322521600).

31313222220 is an abundant number, since it is smaller than the sum of its proper divisors (71331820980).

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

31313222220 is a wasteful number, since it uses less digits than its factorization.

31313222220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9308 (or 9306 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 21.

Adding to 31313222220 its reverse (2222231313), we get a palindrome (33535453533).

The spelling of 31313222220 in words is "thirty-one billion, three hundred thirteen million, two hundred twenty-two thousand, two hundred twenty".