21021221002220 has 12 divisors (see below), whose sum is σ = 44144564104704. Its totient is φ = 8408488400880.

The previous prime is 21021221002157. The next prime is 21021221002237. The reversal of 21021221002220 is 2220012212012.

It is a happy number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 525530525036 + ... + 525530525075.

It is an arithmetic number, because the mean of its divisors is an integer number (3678713675392).

Almost surely, 2^{21021221002220} is an apocalyptic number.

21021221002220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21021221002220 is an abundant number, since it is smaller than the sum of its proper divisors (23123343102484).

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

21021221002220 is a wasteful number, since it uses less digits than its factorization.

21021221002220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1051061050120 (or 1051061050118 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 17.

Adding to 21021221002220 its reverse (2220012212012), we get a palindrome (23241233214232).

The spelling of 21021221002220 in words is "twenty-one trillion, twenty-one billion, two hundred twenty-one million, two thousand, two hundred twenty".