21100100020121 has 4 divisors (see below), whose sum is σ = 21100164067200. Its totient is φ = 21100035973044.

The previous prime is 21100100020099. The next prime is 21100100020249. The reversal of 21100100020121 is 12102000100112.

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 a de Polignac number, because none of the positive numbers 2^k-21100100020121 is a prime.

It is a super-2 number, since 2×21100100020121² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21100100020921) 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, 31526801 + ... + 32189118.

It is an arithmetic number, because the mean of its divisors is an integer number (5275041016800).

Almost surely, 2^{21100100020121} is an apocalyptic number.

It is an amenable number.

21100100020121 is a deficient number, since it is larger than the sum of its proper divisors (64047079).

21100100020121 is an equidigital number, since it uses as much as digits as its factorization.

21100100020121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64047078.

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 21100100020121 its reverse (12102000100112), we get a palindrome (33202100120233).

The spelling of 21100100020121 in words is "twenty-one trillion, one hundred billion, one hundred million, twenty thousand, one hundred twenty-one".