21622015621 has 2 divisors, whose sum is σ = 21622015622. Its totient is φ = 21622015620.

The previous prime is 21622015609. The next prime is 21622015631. The reversal of 21622015621 is 12651022612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19856755396 + 1765260225 = 140914^2 + 42015^2 .

It is a cyclic number.

It is not a de Polignac number, because 21622015621 - 2⁵ = 21622015589 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21622015621.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21622015631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10811007810 + 10811007811.

It is an arithmetic number, because the mean of its divisors is an integer number (10811007811).

Almost surely, 2^21622015621 is an apocalyptic number.

It is an amenable number.

21622015621 is a deficient number, since it is larger than the sum of its proper divisors (1).

21622015621 is an equidigital number, since it uses as much as digits as its factorization.

21622015621 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2880, while the sum is 28.

The spelling of 21622015621 in words is "twenty-one billion, six hundred twenty-two million, fifteen thousand, six hundred twenty-one".