21200122021221 has 96 divisors (see below), whose sum is σ = 36377036841600. Its totient is φ = 11728688371200.

The previous prime is 21200122021159. The next prime is 21200122021271. The reversal of 21200122021221 is 12212022100212.

It is a happy number.

21200122021221 is a `hidden beast` number, since 2 + 1 + 200 + 1 + 220 + 21 + 221 = 666.

It is not a de Polignac number, because 21200122021221 - 2¹⁹ = 21200121496933 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21200122021194 and 21200122021203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21200122021271) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 43286691 + ... + 43773711.

It is an arithmetic number, because the mean of its divisors is an integer number (378927467100).

Almost surely, 2^{21200122021221} is an apocalyptic number.

It is an amenable number.

21200122021221 is a deficient number, since it is larger than the sum of its proper divisors (15176914820379).

21200122021221 is a wasteful number, since it uses less digits than its factorization.

21200122021221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 487427 (or 487424 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

Adding to 21200122021221 its reverse (12212022100212), we get a palindrome (33412144121433).

It can be divided in two parts, 212001 and 22021221, that added together give a palindrome (22233222).

The spelling of 21200122021221 in words is "twenty-one trillion, two hundred billion, one hundred twenty-two million, twenty-one thousand, two hundred twenty-one".