21021221220200 has 48 divisors (see below), whose sum is σ = 48953552491980. Its totient is φ = 8394860418560.

The previous prime is 21021221220119. The next prime is 21021221220283. The reversal of 21021221220200 is 202212212012.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 8338776637636 + 12682444582564 = 2887694^2 + 3561242^2 .

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 11 ways as a sum of consecutive naturals, for example, 85051727 + ... + 85298526.

Almost surely, 2^{21021221220200} is an apocalyptic number.

21021221220200 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21021221220200 is an abundant number, since it is smaller than the sum of its proper divisors (27932331271780).

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

21021221220200 is a wasteful number, since it uses less digits than its factorization.

21021221220200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 170350886 (or 170350877 counting only the distinct ones).

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

Adding to 21021221220200 its reverse (202212212012), we get a palindrome (21223433432212).

The spelling of 21021221220200 in words is "twenty-one trillion, twenty-one billion, two hundred twenty-one million, two hundred twenty thousand, two hundred".