21010022020021 has 4 divisors (see below), whose sum is σ = 21010158440992. Its totient is φ = 21009885599052.

The previous prime is 21010022019979. The next prime is 21010022020067. The reversal of 21010022020021 is 12002022001012.

It is a happy number.

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 21010022020021 - 2²⁹ = 21009485149109 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21010022019983 and 21010022020010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21010022020081) 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, 67979211 + ... + 68287576.

It is an arithmetic number, because the mean of its divisors is an integer number (5252539610248).

Almost surely, 2^{21010022020021} is an apocalyptic number.

It is an amenable number.

21010022020021 is a deficient number, since it is larger than the sum of its proper divisors (136420971).

21010022020021 is a wasteful number, since it uses less digits than its factorization.

21010022020021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 136420970.

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 21010022020021 its reverse (12002022001012), we get a palindrome (33012044021033).

The spelling of 21010022020021 in words is "twenty-one trillion, ten billion, twenty-two million, twenty thousand, twenty-one".