165625 has 12 divisors (see below), whose sum is σ = 210924. Its totient is φ = 130000.

The previous prime is 165617. The next prime is 165653. The reversal of 165625 is 526561.

It can be written as a sum of positive squares in 6 ways, for example, as 121104 + 44521 = 348^2 + 211^2 .

It is not a de Polignac number, because 165625 - 2³ = 165617 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 165625.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3099 + ... + 3151.

It is an arithmetic number, because the mean of its divisors is an integer number (17577).

165625 is a Friedman number, since it can be written as 5^5*(61-6-2), using all its digits and the basic arithmetic operations.

2¹⁶⁵⁶²⁵ is an apocalyptic number.

It is an amenable number.

165625 is a deficient number, since it is larger than the sum of its proper divisors (45299).

165625 is an frugal number, since it uses more digits than its factorization.

165625 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78 (or 58 counting only the distinct ones).

The product of its digits is 1800, while the sum is 25.

The square root of 165625 is about 406.9705149025. The cubic root of 165625 is about 54.9172308757.

Subtracting from 165625 its sum of digits (25), we obtain a triangular number (165600 = T₅₇₅).

It can be divided in two parts, 1656 and 25, that added together give a square (1681 = 41²).

The spelling of 165625 in words is "one hundred sixty-five thousand, six hundred twenty-five".