165405503 has 4 divisors (see below), whose sum is σ = 169875960. Its totient is φ = 160935048.

The previous prime is 165405481. The next prime is 165405509. The reversal of 165405503 is 305504561.

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 165405503 - 2²² = 161211199 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165405509) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2235173 + ... + 2235246.

It is an arithmetic number, because the mean of its divisors is an integer number (42468990).

Almost surely, 2^165405503 is an apocalyptic number.

165405503 is a deficient number, since it is larger than the sum of its proper divisors (4470457).

165405503 is an equidigital number, since it uses as much as digits as its factorization.

165405503 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4470456.

The product of its (nonzero) digits is 9000, while the sum is 29.

The square root of 165405503 is about 12861.0070756531. The cubic root of 165405503 is about 548.9296019124.

The spelling of 165405503 in words is "one hundred sixty-five million, four hundred five thousand, five hundred three".