21222002020021 has 4 divisors (see below), whose sum is σ = 23151274930944. Its totient is φ = 19292729109100.

The previous prime is 21222002020001. The next prime is 21222002020049. The reversal of 21222002020021 is 12002020022212.

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 21222002020021 - 2¹¹ = 21222002017973 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21222002019977 and 21222002020004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21222002020001) 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, 964636455445 + ... + 964636455466.

It is an arithmetic number, because the mean of its divisors is an integer number (5787818732736).

Almost surely, 2^{21222002020021} is an apocalyptic number.

It is an amenable number.

21222002020021 is a deficient number, since it is larger than the sum of its proper divisors (1929272910923).

21222002020021 is a wasteful number, since it uses less digits than its factorization.

21222002020021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1929272910922.

The product of its (nonzero) digits is 128, while the sum is 16.

Adding to 21222002020021 its reverse (12002020022212), we get a palindrome (33224022042233).

The spelling of 21222002020021 in words is "twenty-one trillion, two hundred twenty-two billion, two million, twenty thousand, twenty-one".