21002100020121 has 32 divisors (see below), whose sum is σ = 30574601773056. Its totient is φ = 12717678240000.

The previous prime is 21002100020089. The next prime is 21002100020147. The reversal of 21002100020121 is 12102000120012.

It is not a de Polignac number, because 21002100020121 - 2⁵ = 21002100020089 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21002100020097 and 21002100020106.

It is not an unprimeable number, because it can be changed into a prime (21002100020171) 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, 185735361 + ... + 185848401.

It is an arithmetic number, because the mean of its divisors is an integer number (955456305408).

Almost surely, 2^{21002100020121} is an apocalyptic number.

It is an amenable number.

21002100020121 is a deficient number, since it is larger than the sum of its proper divisors (9572501752935).

21002100020121 is a wasteful number, since it uses less digits than its factorization.

21002100020121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 117813.

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 21002100020121 its reverse (12102000120012), we get a palindrome (33104100140133).

The spelling of 21002100020121 in words is "twenty-one trillion, two billion, one hundred million, twenty thousand, one hundred twenty-one".