21724215296 has 72 divisors (see below), whose sum is σ = 49683586680. Its totient is φ = 9302814720.

The previous prime is 21724215283. The next prime is 21724215299. The reversal of 21724215296 is 69251242712.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21724215299) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 17647001 + ... + 17648231.

It is an arithmetic number, because the mean of its divisors is an integer number (690049815).

Almost surely, 2^21724215296 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 21724215296, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24841793340).

21724215296 is an abundant number, since it is smaller than the sum of its proper divisors (27959371384).

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

21724215296 is an frugal number, since it uses more digits than its factorization.

21724215296 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2491 (or 1240 counting only the distinct ones).

The product of its digits is 120960, while the sum is 41.

The spelling of 21724215296 in words is "twenty-one billion, seven hundred twenty-four million, two hundred fifteen thousand, two hundred ninety-six".