66503 has 4 divisors (see below), whose sum is σ = 67488. Its totient is φ = 65520.

The previous prime is 66499. The next prime is 66509. The reversal of 66503 is 30566.

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 66503 - 2² = 66499 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 66503.

It is not an unprimeable number, because it can be changed into a prime (66509) 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, 383 + ... + 528.

It is an arithmetic number, because the mean of its divisors is an integer number (16872).

2⁶⁶⁵⁰³ is an apocalyptic number.

66503 is a deficient number, since it is larger than the sum of its proper divisors (985).

66503 is an equidigital number, since it uses as much as digits as its factorization.

66503 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 984.

The product of its (nonzero) digits is 540, while the sum is 20.

The square root of 66503 is about 257.8817558495. The cubic root of 66503 is about 40.5148043221.

Subtracting from 66503 its reverse (30566), we obtain a cube (35937 = 33³).

The spelling of 66503 in words is "sixty-six thousand, five hundred three".