165665432554440 has 256 divisors, whose sum is σ = 611731759403520. Its totient is φ = 34951071006720.

The previous prime is 165665432554439. The next prime is 165665432554493. The reversal of 165665432554440 is 44455234566561.

It is a Harshad number since it is a multiple of its sum of digits (60).

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 153225822 + ... + 154303218.

It is an arithmetic number, because the mean of its divisors is an integer number (2389577185170).

Almost surely, 2^{165665432554440} is an apocalyptic number.

165665432554440 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 165665432554440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (305865879701760).

165665432554440 is an abundant number, since it is smaller than the sum of its proper divisors (446066326849080).

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

165665432554440 is a wasteful number, since it uses less digits than its factorization.

165665432554440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1091512 (or 1091508 counting only the distinct ones).

The product of its (nonzero) digits is 207360000, while the sum is 60.

The spelling of 165665432554440 in words is "one hundred sixty-five trillion, six hundred sixty-five billion, four hundred thirty-two million, five hundred fifty-four thousand, four hundred forty".