205503 has 4 divisors (see below), whose sum is σ = 274008. Its totient is φ = 137000.

The previous prime is 205493. The next prime is 205507. The reversal of 205503 is 305502.

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 205503 - 2⁴ = 205487 is a prime.

It is a D-number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205507) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 34248 + ... + 34253.

It is an arithmetic number, because the mean of its divisors is an integer number (68502).

2²⁰⁵⁵⁰³ is an apocalyptic number.

205503 is a deficient number, since it is larger than the sum of its proper divisors (68505).

205503 is an equidigital number, since it uses as much as digits as its factorization.

205503 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68504.

The product of its (nonzero) digits is 150, while the sum is 15.

The square root of 205503 is about 453.3243871666. The cubic root of 205503 is about 59.0118715937.

Subtracting 205503 from its reverse (305502), we obtain a palindrome (99999).

The spelling of 205503 in words is "two hundred five thousand, five hundred three".