21782732544 has 180 divisors, whose sum is σ = 67777658256. Its totient is φ = 6945067008.

The previous prime is 21782732539. The next prime is 21782732599. The reversal of 21782732544 is 44523728712.

21782732544 is a `hidden beast` number, since 2 + 1 + 78 + 2 + 7 + 32 + 544 = 666.

It is a self number, because there is not a number n which added to its sum of digits gives 21782732544.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 454092 + ... + 499764.

Almost surely, 2^21782732544 is an apocalyptic number.

21782732544 is a gapful number since it is divisible by the number (24) 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 21782732544, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33888829128).

21782732544 is an abundant number, since it is smaller than the sum of its proper divisors (45994925712).

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

21782732544 is an equidigital number, since it uses as much as digits as its factorization.

21782732544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45724 (or 45701 counting only the distinct ones).

The product of its digits is 752640, while the sum is 45.

The spelling of 21782732544 in words is "twenty-one billion, seven hundred eighty-two million, seven hundred thirty-two thousand, five hundred forty-four".