21724937520 has 320 divisors, whose sum is σ = 80469849600. Its totient is φ = 4778680320.

The previous prime is 21724937503. The next prime is 21724937527. The reversal of 21724937520 is 2573942712.

It is not an unprimeable number, because it can be changed into a prime (21724937527) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 2019516 + ... + 2030244.

It is an arithmetic number, because the mean of its divisors is an integer number (251468280).

Almost surely, 2^21724937520 is an apocalyptic number.

21724937520 is a gapful number since it is divisible by the number (20) 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 21724937520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40234924800).

21724937520 is an abundant number, since it is smaller than the sum of its proper divisors (58744912080).

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

21724937520 is a wasteful number, since it uses less digits than its factorization.

21724937520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10828 (or 10822 counting only the distinct ones).

The product of its (nonzero) digits is 211680, while the sum is 42.

The spelling of 21724937520 in words is "twenty-one billion, seven hundred twenty-four million, nine hundred thirty-seven thousand, five hundred twenty".