18436820544 has 168 divisors, whose sum is σ = 56300156640. Its totient is φ = 5751724032.

The previous prime is 18436820531. The next prime is 18436820551. The reversal of 18436820544 is 44502863481.

18436820544 is a `hidden beast` number, since 1 + 8 + 43 + 68 + 2 + 0 + 544 = 666.

It is a self number, because there is not a number n which added to its sum of digits gives 18436820544.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 898204 + ... + 918500.

It is an arithmetic number, because the mean of its divisors is an integer number (335119980).

Almost surely, 2^18436820544 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18436820544, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28150078320).

18436820544 is an abundant number, since it is smaller than the sum of its proper divisors (37863336096).

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

18436820544 is a wasteful number, since it uses less digits than its factorization.

18436820544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20417 (or 20404 counting only the distinct ones).

The product of its (nonzero) digits is 737280, while the sum is 45.

The spelling of 18436820544 in words is "eighteen billion, four hundred thirty-six million, eight hundred twenty thousand, five hundred forty-four".