31103312220 has 144 divisors (see below), whose sum is σ = 98262859968. Its totient is φ = 7956264960.

The previous prime is 31103312209. The next prime is 31103312281. The reversal of 31103312220 is 2221330113.

31103312220 is a `hidden beast` number, since 3 + 110 + 331 + 2 + 220 = 666.

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 = 31103312193 and 31103312202.

It is a congruent number.

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, 439972 + ... + 505748.

It is an arithmetic number, because the mean of its divisors is an integer number (682380972).

Almost surely, 2^31103312220 is an apocalyptic number.

31103312220 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 31103312220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (49131429984).

31103312220 is an abundant number, since it is smaller than the sum of its proper divisors (67159547748).

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

31103312220 is a wasteful number, since it uses less digits than its factorization.

31103312220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 65900 (or 65895 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 18.

Adding to 31103312220 its reverse (2221330113), we get a palindrome (33324642333).

The spelling of 31103312220 in words is "thirty-one billion, one hundred three million, three hundred twelve thousand, two hundred twenty".