2221212120 has 128 divisors (see below), whose sum is σ = 7141616640. Its totient is φ = 551232000.

The previous prime is 2221212113. The next prime is 2221212121. The reversal of 2221212120 is 212121222.

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 2221212120.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2221212121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 91245 + ... + 112995.

It is an arithmetic number, because the mean of its divisors is an integer number (55793880).

Almost surely, 2^2221212120 is an apocalyptic number.

2221212120 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 2221212120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3570808320).

2221212120 is an abundant number, since it is smaller than the sum of its proper divisors (4920404520).

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

2221212120 is a wasteful number, since it uses less digits than its factorization.

2221212120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21825 (or 21821 counting only the distinct ones).

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

The square root of 2221212120 is about 47129.7371093877. The cubic root of 2221212120 is about 1304.7581295991.

Adding to 2221212120 its reverse (212121222), we get a palindrome (2433333342).

It can be divided in two parts, 2 and 221212120, that added together give a palindrome (221212122).

The spelling of 2221212120 in words is "two billion, two hundred twenty-one million, two hundred twelve thousand, one hundred twenty".