21221012021200 has 60 divisors (see below), whose sum is σ = 50983933288300. Its totient is φ = 8488329569280.

The previous prime is 21221012021159. The next prime is 21221012021233. The reversal of 21221012021200 is 212021012212.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 1719885365136 + 19501126656064 = 1311444^2 + 4416008^2 .

It is a Harshad number since it is a multiple of its sum of digits (16).

It is a congruent 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 11 ways as a sum of consecutive naturals, for example, 75017626 + ... + 75299974.

Almost surely, 2^{21221012021200} is an apocalyptic number.

21221012021200 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21221012021200 is an abundant number, since it is smaller than the sum of its proper divisors (29762921267100).

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

21221012021200 is a wasteful number, since it uses less digits than its factorization.

21221012021200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 470264 (or 470253 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 21221012021200 its reverse (212021012212), we get a palindrome (21433033033412).

The spelling of 21221012021200 in words is "twenty-one trillion, two hundred twenty-one billion, twelve million, twenty-one thousand, two hundred".