165403 has 4 divisors (see below), whose sum is σ = 189040. Its totient is φ = 141768.

The previous prime is 165397. The next prime is 165437. The reversal of 165403 is 304561.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 165403 - 2¹³ = 157211 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (165443) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11808 + ... + 11821.

It is an arithmetic number, because the mean of its divisors is an integer number (47260).

2¹⁶⁵⁴⁰³ is an apocalyptic number.

165403 is a deficient number, since it is larger than the sum of its proper divisors (23637).

165403 is an equidigital number, since it uses as much as digits as its factorization.

165403 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23636.

The product of its (nonzero) digits is 360, while the sum is 19.

The square root of 165403 is about 406.6976764133. The cubic root of 165403 is about 54.8926833005.

Adding to 165403 its reverse (304561), we get a palindrome (469964).

The spelling of 165403 in words is "one hundred sixty-five thousand, four hundred three".