2211221220 has 96 divisors (see below), whose sum is σ = 6809660928. Its totient is φ = 532710912.

The previous prime is 2211221209. The next prime is 2211221249. The reversal of 2211221220 is 221221122.

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 2211221220.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 6502 + ... + 66818.

It is an arithmetic number, because the mean of its divisors is an integer number (70933968).

Almost surely, 2^2211221220 is an apocalyptic number.

2211221220 is a gapful number since it is divisible by the number (20) 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 2211221220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3404830464).

2211221220 is an abundant number, since it is smaller than the sum of its proper divisors (4598439708).

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

2211221220 is a wasteful number, since it uses less digits than its factorization.

2211221220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60389 (or 60387 counting only the distinct ones).

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

The square root of 2211221220 is about 47023.6240628049. The cubic root of 2211221220 is about 1302.7989438137.

Adding to 2211221220 its reverse (221221122), we get a palindrome (2432442342).

The spelling of 2211221220 in words is "two billion, two hundred eleven million, two hundred twenty-one thousand, two hundred twenty".