21713598720 has 720 divisors, whose sum is σ = 86187467520. Its totient is φ = 5175705600.

The previous prime is 21713598689. The next prime is 21713598757. The reversal of 21713598720 is 2789531712.

21713598720 is a `hidden beast` number, since 21 + 7 + 13 + 598 + 7 + 20 = 666.

It is a tau number, because it is divible by the number of its divisors (720).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 90097800 + ... + 90098040.

It is an arithmetic number, because the mean of its divisors is an integer number (119704816).

Almost surely, 2^21713598720 is an apocalyptic number.

21713598720 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 21713598720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43093733760).

21713598720 is an abundant number, since it is smaller than the sum of its proper divisors (64473868800).

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

21713598720 is a wasteful number, since it uses less digits than its factorization.

21713598720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 364 (or 341 counting only the distinct ones).

The product of its (nonzero) digits is 211680, while the sum is 45.

The spelling of 21713598720 in words is "twenty-one billion, seven hundred thirteen million, five hundred ninety-eight thousand, seven hundred twenty".