165405219840 has 528 divisors, whose sum is σ = 663393070080. Its totient is φ = 37322588160.

The previous prime is 165405219803. The next prime is 165405219869. The reversal of 165405219840 is 48912504561.

165405219840 is a `hidden beast` number, since 1 + 6 + 5 + 40 + 521 + 9 + 84 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

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, 25478995 + ... + 25485485.

Almost surely, 2^165405219840 is an apocalyptic number.

165405219840 is a gapful number since it is divisible by the number (10) 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 165405219840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (331696535040).

165405219840 is an abundant number, since it is smaller than the sum of its proper divisors (497987850240).

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

165405219840 is a wasteful number, since it uses less digits than its factorization.

165405219840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6608 (or 6587 counting only the distinct ones).

The product of its (nonzero) digits is 345600, while the sum is 45.

The spelling of 165405219840 in words is "one hundred sixty-five billion, four hundred five million, two hundred nineteen thousand, eight hundred forty".