21601553332604 has 72 divisors (see below), whose sum is σ = 44314048536912. Its totient is φ = 9186355825920.

The previous prime is 21601553332577. The next prime is 21601553332613. The reversal of 21601553332604 is 40623335510612.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 379899344 + ... + 379956200.

It is an arithmetic number, because the mean of its divisors is an integer number (615472896346).

Almost surely, 2^{21601553332604} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21601553332604, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22157024268456).

21601553332604 is an abundant number, since it is smaller than the sum of its proper divisors (22712495204308).

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

21601553332604 is a wasteful number, since it uses less digits than its factorization.

21601553332604 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71803 (or 71794 counting only the distinct ones).

The product of its (nonzero) digits is 388800, while the sum is 41.

The spelling of 21601553332604 in words is "twenty-one trillion, six hundred one billion, five hundred fifty-three million, three hundred thirty-two thousand, six hundred four".