21100021122021 has 4 divisors (see below), whose sum is σ = 28133361496032. Its totient is φ = 14066680748012.

The previous prime is 21100021122001. The next prime is 21100021122043. The reversal of 21100021122021 is 12022112000112.

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 21100021122021 - 2²¹ = 21100019024869 is a prime.

It is a super-2 number, since 2×21100021122021² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21100021122001) 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, 3516670187001 + ... + 3516670187006.

It is an arithmetic number, because the mean of its divisors is an integer number (7033340374008).

Almost surely, 2^{21100021122021} is an apocalyptic number.

It is an amenable number.

21100021122021 is a deficient number, since it is larger than the sum of its proper divisors (7033340374011).

21100021122021 is an equidigital number, since it uses as much as digits as its factorization.

21100021122021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7033340374010.

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 21100021122021 its reverse (12022112000112), we get a palindrome (33122133122133).

The spelling of 21100021122021 in words is "twenty-one trillion, one hundred billion, twenty-one million, one hundred twenty-two thousand, twenty-one".