661304503 has 2 divisors, whose sum is σ = 661304504. Its totient is φ = 661304502.

The previous prime is 661304467. The next prime is 661304513. The reversal of 661304503 is 305403166.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 661304503 - 2⁹ = 661303991 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661304513) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330652251 + 330652252.

It is an arithmetic number, because the mean of its divisors is an integer number (330652252).

Almost surely, 2^661304503 is an apocalyptic number.

661304503 is a deficient number, since it is larger than the sum of its proper divisors (1).

661304503 is an equidigital number, since it uses as much as digits as its factorization.

661304503 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6480, while the sum is 28.

The square root of 661304503 is about 25715.8414795239. The cubic root of 661304503 is about 871.2320163404.

Adding to 661304503 its reverse (305403166), we get a palindrome (966707669).

The spelling of 661304503 in words is "six hundred sixty-one million, three hundred four thousand, five hundred three".