66540503 has 4 divisors (see below), whose sum is σ = 66556848. Its totient is φ = 66524160.

The previous prime is 66540473. The next prime is 66540511. The reversal of 66540503 is 30504566.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 66540503 - 2⁸ = 66540247 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 (66540553) 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, 3350 + ... + 12012.

It is an arithmetic number, because the mean of its divisors is an integer number (16639212).

Almost surely, 2^66540503 is an apocalyptic number.

66540503 is a deficient number, since it is larger than the sum of its proper divisors (16345).

66540503 is an equidigital number, since it uses as much as digits as its factorization.

66540503 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16344.

The product of its (nonzero) digits is 10800, while the sum is 29.

The square root of 66540503 is about 8157.2362353925. The cubic root of 66540503 is about 405.2241872132.

The spelling of 66540503 in words is "sixty-six million, five hundred forty thousand, five hundred three".