21729606584 has 128 divisors (see below), whose sum is σ = 50682931200. Its totient is φ = 8521390080.

The previous prime is 21729606559. The next prime is 21729606589. The reversal of 21729606584 is 48560692712.

It is a super-2 number, since 2×21729606584² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21729606589) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 9782594 + ... + 9784814.

It is an arithmetic number, because the mean of its divisors is an integer number (395960400).

Almost surely, 2^21729606584 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 21729606584, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25341465600).

21729606584 is an abundant number, since it is smaller than the sum of its proper divisors (28953324616).

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

21729606584 is a wasteful number, since it uses less digits than its factorization.

21729606584 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2533 (or 2529 counting only the distinct ones).

The product of its (nonzero) digits is 1451520, while the sum is 50.

The spelling of 21729606584 in words is "twenty-one billion, seven hundred twenty-nine million, six hundred six thousand, five hundred eighty-four".