165906 has 24 divisors (see below), whose sum is σ = 387660. Its totient is φ = 50976.

The previous prime is 165901. The next prime is 165931. The reversal of 165906 is 609561.

165906 = 65² + 66² + ... + 91².

165906 is a `hidden beast` number, since 1 + 659 + 0 + 6 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 140625 + 25281 = 375^2 + 159^2 .

It is a plaindrome in base 14.

It is a zygodrome in base 14.

It is a self number, because there is not a number n which added to its sum of digits gives 165906.

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

165906 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

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 11 ways as a sum of consecutive naturals, for example, 121 + ... + 588.

2¹⁶⁵⁹⁰⁶ is an apocalyptic number.

165906 is an abundant number, since it is smaller than the sum of its proper divisors (221754).

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

165906 is a wasteful number, since it uses less digits than its factorization.

165906 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 730 (or 727 counting only the distinct ones).

The product of its (nonzero) digits is 1620, while the sum is 27.

The square root of 165906 is about 407.3156024510. The cubic root of 165906 is about 54.9482709218.

The spelling of 165906 in words is "one hundred sixty-five thousand, nine hundred six".