221021200000000 has 198 divisors, whose sum is σ = 552283915472678. Its totient is φ = 88408320000000.

The previous prime is 221021199999989. The next prime is 221021200000021. The reversal of 221021200000000 is 2120122.

It can be written as a sum of positive squares in 9 ways, for example, as 51220702314496 + 169800497685504 = 7156864^2 + 13030752^2 .

It is a Harshad number since it is a multiple of its sum of digits (10).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 399723724 + ... + 400276276.

Almost surely, 2^{221021200000000} is an apocalyptic number.

221021200000000 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 221021200000000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (276141957736339).

221021200000000 is an abundant number, since it is smaller than the sum of its proper divisors (331262715472678).

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

221021200000000 is an frugal number, since it uses more digits than its factorization.

221021200000000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 552613 (or 552560 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 10.

Adding to 221021200000000 its reverse (2120122), we get a palindrome (221021202120122).

The spelling of 221021200000000 in words is "two hundred twenty-one trillion, twenty-one billion, two hundred million", and thus it is an aban number.