165609400320 has 1728 divisors, whose sum is σ = 748185984000. Its totient is φ = 33814609920.

The previous prime is 165609400303. The next prime is 165609400321. The reversal of 165609400320 is 23004906561.

It is a happy number.

165609400320 is a `hidden beast` number, since 1 + 6 + 5 + 609 + 40 + 0 + 3 + 2 + 0 = 666.

It is a super-2 number, since 2×165609400320² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165609400321) by changing a digit.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 5342238705 + ... + 5342238735.

It is an arithmetic number, because the mean of its divisors is an integer number (432978000).

Almost surely, 2^165609400320 is an apocalyptic number.

165609400320 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 165609400320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (374092992000).

165609400320 is an abundant number, since it is smaller than the sum of its proper divisors (582576583680).

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

165609400320 is a wasteful number, since it uses less digits than its factorization.

165609400320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 111 (or 61 counting only the distinct ones).

The product of its (nonzero) digits is 38880, while the sum is 36.

The spelling of 165609400320 in words is "one hundred sixty-five billion, six hundred nine million, four hundred thousand, three hundred twenty".