21621266225436 has 24 divisors (see below), whose sum is σ = 50450632735104. Its totient is φ = 7206944235760.

The previous prime is 21621266225413. The next prime is 21621266225441. The reversal of 21621266225436 is 63452266212612.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17438970 + ... + 18637601.

It is an arithmetic number, because the mean of its divisors is an integer number (2102109697296).

Almost surely, 2^{21621266225436} is an apocalyptic number.

It is an amenable number.

21621266225436 is an abundant number, since it is smaller than the sum of its proper divisors (28829366509668).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21621266225436 is a wasteful number, since it uses less digits than its factorization.

21621266225436 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36126521 (or 36126519 counting only the distinct ones).

The product of its digits is 2488320, while the sum is 48.

The spelling of 21621266225436 in words is "twenty-one trillion, six hundred twenty-one billion, two hundred sixty-six million, two hundred twenty-five thousand, four hundred thirty-six".