21221522265563 has 16 divisors (see below), whose sum is σ = 22661848124160. Its totient is φ = 19828455091200.

The previous prime is 21221522265487. The next prime is 21221522265623. The reversal of 21221522265563 is 36556222512212.

It is a cyclic number.

It is not a de Polignac number, because 21221522265563 - 2²⁴ = 21221505488347 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21221522295563) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 66079031 + ... + 66399407.

It is an arithmetic number, because the mean of its divisors is an integer number (1416365507760).

Almost surely, 2^{21221522265563} is an apocalyptic number.

21221522265563 is a deficient number, since it is larger than the sum of its proper divisors (1440325858597).

21221522265563 is a wasteful number, since it uses less digits than its factorization.

21221522265563 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 394118.

The product of its digits is 864000, while the sum is 44.

Adding to 21221522265563 its reverse (36556222512212), we get a palindrome (57777744777775).

The spelling of 21221522265563 in words is "twenty-one trillion, two hundred twenty-one billion, five hundred twenty-two million, two hundred sixty-five thousand, five hundred sixty-three".