21726518784 has 80 divisors (see below), whose sum is σ = 57941066832. Its totient is φ = 7234633728.

The previous prime is 21726518783. The next prime is 21726518833. The reversal of 21726518784 is 48781562712.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21726518783) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1579842 + ... + 1593534.

Almost surely, 2^21726518784 is an apocalyptic number.

21726518784 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21726518784, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28970533416).

21726518784 is an abundant number, since it is smaller than the sum of its proper divisors (36214548048).

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

21726518784 is a wasteful number, since it uses less digits than its factorization.

21726518784 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14747 (or 14731 counting only the distinct ones).

The product of its digits is 1505280, while the sum is 51.

The spelling of 21726518784 in words is "twenty-one billion, seven hundred twenty-six million, five hundred eighteen thousand, seven hundred eighty-four".