21021220010021 has 32 divisors (see below), whose sum is σ = 27068198707200. Its totient is φ = 15843284942400.

The previous prime is 21021220009969. The next prime is 21021220010059. The reversal of 21021220010021 is 12001002212012.

It is a cyclic number.

It is not a de Polignac number, because 21021220010021 - 2²⁶ = 21021152901157 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21021220009978 and 21021220010005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021220010071) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2098055 + ... + 6815003.

It is an arithmetic number, because the mean of its divisors is an integer number (845881209600).

Almost surely, 2^{21021220010021} is an apocalyptic number.

It is an amenable number.

21021220010021 is a deficient number, since it is larger than the sum of its proper divisors (6046978697179).

21021220010021 is a wasteful number, since it uses less digits than its factorization.

21021220010021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4718865.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 21021220010021 its reverse (12001002212012), we get a palindrome (33022222222033).

The spelling of 21021220010021 in words is "twenty-one trillion, twenty-one billion, two hundred twenty million, ten thousand, twenty-one".