21100100101021 has 4 divisors (see below), whose sum is σ = 21114176220000. Its totient is φ = 21086023982044.

The previous prime is 21100100101019. The next prime is 21100100101027. The reversal of 21100100101021 is 12010100100112.

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 21100100101021 - 2¹ = 21100100101019 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21100100100989 and 21100100101007.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21100100101027) 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, 7038057241 + ... + 7038060238.

It is an arithmetic number, because the mean of its divisors is an integer number (5278544055000).

Almost surely, 2^{21100100101021} is an apocalyptic number.

It is an amenable number.

21100100101021 is a deficient number, since it is larger than the sum of its proper divisors (14076118979).

21100100101021 is a wasteful number, since it uses less digits than its factorization.

21100100101021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14076118978.

The product of its (nonzero) digits is 4, while the sum is 10.

Adding to 21100100101021 its reverse (12010100100112), we get a palindrome (33110200201133).

Subtracting from 21100100101021 its reverse (12010100100112), we obtain a palindrome (9090000000909).

The spelling of 21100100101021 in words is "twenty-one trillion, one hundred billion, one hundred million, one hundred one thousand, twenty-one".