8181815616 has 336 divisors, whose sum is σ = 26836420800. Its totient is φ = 2429844480.

The previous prime is 8181815597. The next prime is 8181815627. The reversal of 8181815616 is 6165181818.

It is a happy number.

8181815616 is a `hidden beast` number, since 8 + 1 + 8 + 1 + 81 + 561 + 6 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 21587715 + ... + 21588093.

It is an arithmetic number, because the mean of its divisors is an integer number (79870300).

Almost surely, 2^8181815616 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 8181815616, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (13418210400).

8181815616 is an abundant number, since it is smaller than the sum of its proper divisors (18654605184).

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

8181815616 is a wasteful number, since it uses less digits than its factorization.

8181815616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 475 (or 428 counting only the distinct ones).

The product of its digits is 92160, while the sum is 45.

The square root of 8181815616 is about 90453.3891902343. The cubic root of 8181815616 is about 2015.0379480033.

The spelling of 8181815616 in words is "eight billion, one hundred eighty-one million, eight hundred fifteen thousand, six hundred sixteen".