21200121321220 has 12 divisors (see below), whose sum is σ = 44520254774604. Its totient is φ = 8480048528480.

The previous prime is 21200121321193. The next prime is 21200121321251. The reversal of 21200121321220 is 2212312100212.

It can be written as a sum of positive squares in 2 ways, for example, as 16936912240704 + 4263209080516 = 4115448^2 + 2064754^2 .

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, 530003033011 + ... + 530003033050.

It is an arithmetic number, because the mean of its divisors is an integer number (3710021231217).

Almost surely, 2^{21200121321220} is an apocalyptic number.

21200121321220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21200121321220 is an abundant number, since it is smaller than the sum of its proper divisors (23320133453384).

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

21200121321220 is a wasteful number, since it uses less digits than its factorization.

21200121321220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1060006066070 (or 1060006066068 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 19.

Adding to 21200121321220 its reverse (2212312100212), we get a palindrome (23412433421432).

The spelling of 21200121321220 in words is "twenty-one trillion, two hundred billion, one hundred twenty-one million, three hundred twenty-one thousand, two hundred twenty".