21847820544 has 216 divisors, whose sum is σ = 68994516864. Its totient is φ = 6594048000.

The previous prime is 21847820471. The next prime is 21847820551. The reversal of 21847820544 is 44502874812.

21847820544 is a `hidden beast` number, since 2 + 1 + 84 + 7 + 8 + 20 + 544 = 666.

It is a self number, because there is not a number n which added to its sum of digits gives 21847820544.

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 23 ways as a sum of consecutive naturals, for example, 6866634 + ... + 6869814.

Almost surely, 2^21847820544 is an apocalyptic number.

21847820544 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 21847820544, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34497258432).

21847820544 is an abundant number, since it is smaller than the sum of its proper divisors (47146696320).

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

21847820544 is a wasteful number, since it uses less digits than its factorization.

21847820544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3485 (or 3468 counting only the distinct ones).

The product of its (nonzero) digits is 573440, while the sum is 45.

The spelling of 21847820544 in words is "twenty-one billion, eight hundred forty-seven million, eight hundred twenty thousand, five hundred forty-four".