2221121220 has 48 divisors (see below), whose sum is σ = 6274195200. Its totient is φ = 587055616.

The previous prime is 2221121173. The next prime is 2221121239. The reversal of 2221121220 is 221211222.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 2221121220.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 157020 + ... + 170579.

It is an arithmetic number, because the mean of its divisors is an integer number (130712400).

Almost surely, 2^2221121220 is an apocalyptic number.

2221121220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2221121220 is an abundant number, since it is smaller than the sum of its proper divisors (4053073980).

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

2221121220 is a wasteful number, since it uses less digits than its factorization.

2221121220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 327724 (or 327722 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 15.

The square root of 2221121220 is about 47128.7727402274. The cubic root of 2221121220 is about 1304.7403308890.

Adding to 2221121220 its reverse (221211222), we get a palindrome (2442332442).

The spelling of 2221121220 in words is "two billion, two hundred twenty-one million, one hundred twenty-one thousand, two hundred twenty".