165620 has 54 divisors (see below), whose sum is σ = 438102. Its totient is φ = 52416.

The previous prime is 165617. The next prime is 165653. The reversal of 165620 is 26561.

165620 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 3 ways, for example, as 784 + 164836 = 28^2 + 406^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 165592 and 165601.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 12734 + ... + 12746.

It is an arithmetic number, because the mean of its divisors is an integer number (8113).

2¹⁶⁵⁶²⁰ is an apocalyptic number.

165620 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 165620, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (219051).

165620 is an abundant number, since it is smaller than the sum of its proper divisors (272482).

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

165620 is a wasteful number, since it uses less digits than its factorization.

165620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49 (or 27 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 20.

The square root of 165620 is about 406.9643719050. The cubic root of 165620 is about 54.9166782439.

Subtracting from 165620 its sum of digits (20), we obtain a triangular number (165600 = T₅₇₅).

Multiplying 165620 by its sum of digits (20), we get a square (3312400 = 1820²).

165620 divided by its sum of digits (20) gives a square (8281 = 91²).

The spelling of 165620 in words is "one hundred sixty-five thousand, six hundred twenty".