21100022102021 has 4 divisors (see below), whose sum is σ = 21308933212044. Its totient is φ = 20891110992000.

The previous prime is 21100022102009. The next prime is 21100022102041. The reversal of 21100022102021 is 12020122000112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 8699137324900 + 12400884777121 = 2949430^2 + 3521489^2 .

It is a cyclic number.

It is not a de Polignac number, because 21100022102021 - 2³⁸ = 20825144195077 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21100022101987 and 21100022102005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21100022102041) 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, 104455554860 + ... + 104455555061.

It is an arithmetic number, because the mean of its divisors is an integer number (5327233303011).

Almost surely, 2^{21100022102021} is an apocalyptic number.

It is an amenable number.

21100022102021 is a deficient number, since it is larger than the sum of its proper divisors (208911110023).

21100022102021 is a wasteful number, since it uses less digits than its factorization.

21100022102021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 208911110022.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 21100022102021 its reverse (12020122000112), we get a palindrome (33120144102133).

The spelling of 21100022102021 in words is "twenty-one trillion, one hundred billion, twenty-two million, one hundred two thousand, twenty-one".