21120201220 has 12 divisors (see below), whose sum is σ = 44352422604. Its totient is φ = 8448080480.

The previous prime is 21120201211. The next prime is 21120201247. The reversal of 21120201220 is 2210202112.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 9087427584 + 12032773636 = 95328^2 + 109694^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21120201220.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 528005011 + ... + 528005050.

It is an arithmetic number, because the mean of its divisors is an integer number (3696035217).

Almost surely, 2^21120201220 is an apocalyptic number.

21120201220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21120201220 is an abundant number, since it is smaller than the sum of its proper divisors (23232221384).

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

21120201220 is a wasteful number, since it uses less digits than its factorization.

21120201220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1056010070 (or 1056010068 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 21120201220 its reverse (2210202112), we get a palindrome (23330403332).

The spelling of 21120201220 in words is "twenty-one billion, one hundred twenty million, two hundred one thousand, two hundred twenty".