165506393808 has 480 divisors, whose sum is σ = 591689629440. Its totient is φ = 42042654720.

The previous prime is 165506393803. The next prime is 165506393809. The reversal of 165506393808 is 808393605561.

165506393808 is a `hidden beast` number, since 1 + 6 + 550 + 6 + 3 + 9 + 3 + 80 + 8 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165506393803) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 187861528 + ... + 187862408.

It is an arithmetic number, because the mean of its divisors is an integer number (1232686728).

Almost surely, 2^165506393808 is an apocalyptic number.

165506393808 is a gapful number since it is divisible by the number (18) 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 165506393808, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (295844814720).

165506393808 is an abundant number, since it is smaller than the sum of its proper divisors (426183235632).

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

165506393808 is a wasteful number, since it uses less digits than its factorization.

165506393808 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1515 (or 1506 counting only the distinct ones).

The product of its (nonzero) digits is 4665600, while the sum is 54.

The spelling of 165506393808 in words is "one hundred sixty-five billion, five hundred six million, three hundred ninety-three thousand, eight hundred eight".