21110010020021 has 4 divisors (see below), whose sum is σ = 22733856944652. Its totient is φ = 19486163095392.

The previous prime is 21110010020009. The next prime is 21110010020023. The reversal of 21110010020021 is 12002001001112.

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 1077994210225 + 20032015809796 = 1038265^2 + 4475714^2 .

It is a cyclic number.

It is not a de Polignac number, because 21110010020021 - 2²² = 21110005825717 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21110010019984 and 21110010020011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21110010020023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 811923462296 + ... + 811923462321.

It is an arithmetic number, because the mean of its divisors is an integer number (5683464236163).

Almost surely, 2^{21110010020021} is an apocalyptic number.

It is an amenable number.

21110010020021 is a deficient number, since it is larger than the sum of its proper divisors (1623846924631).

21110010020021 is a wasteful number, since it uses less digits than its factorization.

21110010020021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1623846924630.

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

Adding to 21110010020021 its reverse (12002001001112), we get a palindrome (33112011021133).

The spelling of 21110010020021 in words is "twenty-one trillion, one hundred ten billion, ten million, twenty thousand, twenty-one".