21222010021 has 4 divisors (see below), whose sum is σ = 21953803500. Its totient is φ = 20490216544.

The previous prime is 21222010013. The next prime is 21222010097. The reversal of 21222010021 is 12001022212.

It is a happy number.

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 4500933921 + 16721076100 = 67089^2 + 129310^2 .

It is a cyclic number.

It is not a de Polignac number, because 21222010021 - 2³ = 21222010013 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21222009983 and 21222010010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21226010021) 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, 365896696 + ... + 365896753.

It is an arithmetic number, because the mean of its divisors is an integer number (5488450875).

Almost surely, 2^21222010021 is an apocalyptic number.

It is an amenable number.

21222010021 is a deficient number, since it is larger than the sum of its proper divisors (731793479).

21222010021 is an equidigital number, since it uses as much as digits as its factorization.

21222010021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 731793478.

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

Adding to 21222010021 its reverse (12001022212), we get a palindrome (33223032233).

The spelling of 21222010021 in words is "twenty-one billion, two hundred twenty-two million, ten thousand, twenty-one".