21221010100021 has 8 divisors (see below), whose sum is σ = 21337163912000. Its totient is φ = 21105169794720.

The previous prime is 21221010100019. The next prime is 21221010100049. The reversal of 21221010100021 is 12000101012212.

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

It is a cyclic number.

It is not a de Polignac number, because 21221010100021 - 2¹ = 21221010100019 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21221010099974 and 21221010100010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21221010100001) 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, 78240921 + ... + 78511678.

It is an arithmetic number, because the mean of its divisors is an integer number (2667145489000).

Almost surely, 2^{21221010100021} is an apocalyptic number.

It is an amenable number.

21221010100021 is a deficient number, since it is larger than the sum of its proper divisors (116153811979).

21221010100021 is a wasteful number, since it uses less digits than its factorization.

21221010100021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 156753339.

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 21221010100021 its reverse (12000101012212), we get a palindrome (33221111112233).

The spelling of 21221010100021 in words is "twenty-one trillion, two hundred twenty-one billion, ten million, one hundred thousand, twenty-one".