165538 has 8 divisors (see below), whose sum is σ = 255132. Its totient is φ = 80496.

The previous prime is 165533. The next prime is 165541. The reversal of 165538 is 835561.

It can be written as a sum of positive squares in 2 ways, for example, as 142129 + 23409 = 377^2 + 153^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (165533) by changing a digit.

165538 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 (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1045 + ... + 1192.

2¹⁶⁵⁵³⁸ is an apocalyptic number.

165538 is a deficient number, since it is larger than the sum of its proper divisors (89594).

165538 is a wasteful number, since it uses less digits than its factorization.

165538 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2276.

The product of its digits is 3600, while the sum is 28.

The square root of 165538 is about 406.8636135119. The cubic root of 165538 is about 54.9076134953.

It can be divided in two parts, 16553 and 8, that added together give a palindrome (16561).

The spelling of 165538 in words is "one hundred sixty-five thousand, five hundred thirty-eight".