66440503 has 2 divisors, whose sum is σ = 66440504. Its totient is φ = 66440502.

The previous prime is 66440467. The next prime is 66440519. The reversal of 66440503 is 30504466.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66440503 is a prime.

It is equal to p_3920725 and since 66440503 and 3920725 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66440303) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33220251 + 33220252.

It is an arithmetic number, because the mean of its divisors is an integer number (33220252).

Almost surely, 2^66440503 is an apocalyptic number.

66440503 is a deficient number, since it is larger than the sum of its proper divisors (1).

66440503 is an equidigital number, since it uses as much as digits as its factorization.

66440503 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8640, while the sum is 28.

The square root of 66440503 is about 8151.1044036989. The cubic root of 66440503 is about 405.0210891828.

Adding to 66440503 its reverse (30504466), we get a palindrome (96944969).

The spelling of 66440503 in words is "sixty-six million, four hundred forty thousand, five hundred three".