21000200021221 has 8 divisors (see below), whose sum is σ = 21415452768864. Its totient is φ = 20588810090160.

The previous prime is 21000200021209. The next prime is 21000200021231. The reversal of 21000200021221 is 12212000200012.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21000200021221 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000200021231) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 965693166 + ... + 965714911.

It is an arithmetic number, because the mean of its divisors is an integer number (2676931596108).

Almost surely, 2^{21000200021221} is an apocalyptic number.

It is an amenable number.

21000200021221 is a deficient number, since it is larger than the sum of its proper divisors (415252747643).

21000200021221 is a wasteful number, since it uses less digits than its factorization.

21000200021221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1931408291.

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 21000200021221 its reverse (12212000200012), we get a palindrome (33212200221233).

The spelling of 21000200021221 in words is "twenty-one trillion, two hundred million, twenty-one thousand, two hundred twenty-one".