3638554581816 has 320 divisors, whose sum is σ = 12798832654080. Its totient is φ = 938178961920.

The previous prime is 3638554581751. The next prime is 3638554581901. The reversal of 3638554581816 is 6181854558363.

3638554581816 is a `hidden beast` number, since 3 + 6 + 3 + 8 + 5 + 545 + 8 + 1 + 81 + 6 = 666.

3638554581816 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-3 number, since 3×3638554581816³ (a number of 39 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 6569611 + ... + 7101893.

It is an arithmetic number, because the mean of its divisors is an integer number (39996352044).

Almost surely, 2^{3638554581816} is an apocalyptic number.

3638554581816 is a gapful number since it is divisible by the number (36) 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 3638554581816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (6399416327040).

3638554581816 is an abundant number, since it is smaller than the sum of its proper divisors (9160278072264).

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

3638554581816 is a wasteful number, since it uses less digits than its factorization.

3638554581816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 532456 (or 532443 counting only the distinct ones).

The product of its digits is 82944000, while the sum is 63.

The spelling of 3638554581816 in words is "three trillion, six hundred thirty-eight billion, five hundred fifty-four million, five hundred eighty-one thousand, eight hundred sixteen".