21759764800 has 168 divisors, whose sum is σ = 54980393976. Its totient is φ = 8472821760.

The previous prime is 21759764779. The next prime is 21759764809. The reversal of 21759764800 is 846795712.

It can be written as a sum of positive squares in 12 ways, for example, as 8756467776 + 13003297024 = 93576^2 + 114032^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21759764809) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 11616664 + ... + 11618536.

Almost surely, 2^21759764800 is an apocalyptic number.

21759764800 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 21759764800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27490196988).

21759764800 is an abundant number, since it is smaller than the sum of its proper divisors (33220629176).

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

21759764800 is a wasteful number, since it uses less digits than its factorization.

21759764800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2085 (or 2070 counting only the distinct ones).

The product of its (nonzero) digits is 846720, while the sum is 49.

The spelling of 21759764800 in words is "twenty-one billion, seven hundred fifty-nine million, seven hundred sixty-four thousand, eight hundred".