21804318720 has 640 divisors, whose sum is σ = 82215492480. Its totient is φ = 5520752640.

The previous prime is 21804318719. The next prime is 21804318763. The reversal of 21804318720 is 2781340812.

21804318720 is a `hidden beast` number, since 218 + 0 + 431 + 8 + 7 + 2 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (640).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 411402214 + ... + 411402266.

It is an arithmetic number, because the mean of its divisors is an integer number (128461707).

Almost surely, 2^21804318720 is an apocalyptic number.

21804318720 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 21804318720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41107746240).

21804318720 is an abundant number, since it is smaller than the sum of its proper divisors (60411173760).

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

21804318720 is an frugal number, since it uses more digits than its factorization.

21804318720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 131 (or 94 counting only the distinct ones).

The product of its (nonzero) digits is 21504, while the sum is 36.

The spelling of 21804318720 in words is "twenty-one billion, eight hundred four million, three hundred eighteen thousand, seven hundred twenty".