165900 has 72 divisors (see below), whose sum is σ = 555520. Its totient is φ = 37440.

The previous prime is 165887. The next prime is 165901. The reversal of 165900 is 9561.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2061 + ... + 2139.

2¹⁶⁵⁹⁰⁰ is an apocalyptic number.

165900 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 165900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (277760).

165900 is an abundant number, since it is smaller than the sum of its proper divisors (389620).

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

165900 is a wasteful number, since it uses less digits than its factorization.

165900 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 103 (or 96 counting only the distinct ones).

The product of its (nonzero) digits is 270, while the sum is 21.

The square root of 165900 is about 407.3082370883. The cubic root of 165900 is about 54.9476085114.

The spelling of 165900 in words is "one hundred sixty-five thousand, nine hundred".