165398784408018 has 576 divisors, whose sum is σ = 437780695891968. Its totient is φ = 44962371336960.

The previous prime is 165398784408001. The next prime is 165398784408041. The reversal of 165398784408018 is 810804487893561.

It is a happy number.

165398784408018 is a `hidden beast` number, since 1 + 6 + 5 + 3 + 98 + 7 + 8 + 440 + 80 + 18 = 666.

It is an unprimeable number.

It is a polite number, since it can be written in 287 ways as a sum of consecutive naturals, for example, 128116795953 + ... + 128116797243.

It is an arithmetic number, because the mean of its divisors is an integer number (760035930368).

Almost surely, 2^{165398784408018} is an apocalyptic number.

165398784408018 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 165398784408018, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (218890347945984).

165398784408018 is an abundant number, since it is smaller than the sum of its proper divisors (272381911483950).

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

165398784408018 is a wasteful number, since it uses less digits than its factorization.

165398784408018 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1947 (or 1937 counting only the distinct ones).

The product of its (nonzero) digits is 371589120, while the sum is 72.

The spelling of 165398784408018 in words is "one hundred sixty-five trillion, three hundred ninety-eight billion, seven hundred eighty-four million, four hundred eight thousand, eighteen".