312111221220 has 288 divisors, whose sum is σ = 1027512743040. Its totient is φ = 78641176320.

The previous prime is 312111221189. The next prime is 312111221249. The reversal of 312111221220 is 22122111213.

312111221220 is a `hidden beast` number, since 312 + 1 + 112 + 21 + 220 = 666.

It is a super-2 number, since 2×312111221220² (a number of 24 digits) contains 22 as substring.

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 = 312111221193 and 312111221202.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 82067839 + ... + 82071641.

It is an arithmetic number, because the mean of its divisors is an integer number (3567752580).

Almost surely, 2^312111221220 is an apocalyptic number.

312111221220 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 312111221220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (513756371520).

312111221220 is an abundant number, since it is smaller than the sum of its proper divisors (715401521820).

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

312111221220 is a wasteful number, since it uses less digits than its factorization.

312111221220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4280 (or 4253 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 18.

Adding to 312111221220 its reverse (22122111213), we get a palindrome (334233332433).

The spelling of 312111221220 in words is "three hundred twelve billion, one hundred eleven million, two hundred twenty-one thousand, two hundred twenty".