21001022200021 has 4 divisors (see below), whose sum is σ = 21001050898912. Its totient is φ = 21000993501132.

The previous prime is 21001022200013. The next prime is 21001022200027. The reversal of 21001022200021 is 12000222010012.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21001022200021 - 2³ = 21001022200013 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21001022199974 and 21001022200010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001022200027) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13222275 + ... + 14725168.

It is an arithmetic number, because the mean of its divisors is an integer number (5250262724728).

Almost surely, 2^{21001022200021} is an apocalyptic number.

It is an amenable number.

21001022200021 is a deficient number, since it is larger than the sum of its proper divisors (28698891).

21001022200021 is an equidigital number, since it uses as much as digits as its factorization.

21001022200021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28698890.

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

Adding to 21001022200021 its reverse (12000222010012), we get a palindrome (33001244210033).

The spelling of 21001022200021 in words is "twenty-one trillion, one billion, twenty-two million, two hundred thousand, twenty-one".