165985327872 has 1728 divisors, whose sum is σ = 690794818560. Its totient is φ = 38125043712.

The previous prime is 165985327847. The next prime is 165985327919. The reversal of 165985327872 is 278723589561.

165985327872 is a `hidden beast` number, since 1 + 6 + 5 + 98 + 532 + 7 + 8 + 7 + 2 = 666.

It is a tau number, because it is divible by the number of its divisors (1728).

It is a super-2 number, since 2×165985327872² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 3860123883 + ... + 3860123925.

It is an arithmetic number, because the mean of its divisors is an integer number (399765520).

Almost surely, 2^165985327872 is an apocalyptic number.

165985327872 is a gapful number since it is divisible by the number (12) 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 165985327872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (345397409280).

165985327872 is an abundant number, since it is smaller than the sum of its proper divisors (524809490688).

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

165985327872 is a wasteful number, since it uses less digits than its factorization.

165985327872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 143 (or 104 counting only the distinct ones).

The product of its digits is 50803200, while the sum is 63.

The spelling of 165985327872 in words is "one hundred sixty-five billion, nine hundred eighty-five million, three hundred twenty-seven thousand, eight hundred seventy-two".