21809382400 has 297 divisors, whose sum is σ = 59375382303. Its totient is φ = 7939276800.

The previous prime is 21809382367. The next prime is 21809382403. The reversal of 21809382400 is 428390812.

The square root of 21809382400 is 147680.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 5621400576 + 16187981824 = 74976^2 + 127232^2 .

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21809382400.

It is not an unprimeable number, because it can be changed into a prime (21809382403) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 307174365 + ... + 307174435.

Almost surely, 2^21809382400 is an apocalyptic number.

21809382400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

21809382400 is the 147680-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21809382400

21809382400 is an abundant number, since it is smaller than the sum of its proper divisors (37565999903).

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

21809382400 is an equidigital number, since it uses as much as digits as its factorization.

21809382400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 198 (or 91 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 37.

The spelling of 21809382400 in words is "twenty-one billion, eight hundred nine million, three hundred eighty-two thousand, four hundred".