18503493661 has 2 divisors, whose sum is σ = 18503493662. Its totient is φ = 18503493660.

The previous prime is 18503493641. The next prime is 18503493737. The reversal of 18503493661 is 16639430581.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12849356025 + 5654137636 = 113355^2 + 75194^2 .

It is an emirp because it is prime and its reverse (16639430581) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18503493661 - 2⁹ = 18503493149 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18503493611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9251746830 + 9251746831.

It is an arithmetic number, because the mean of its divisors is an integer number (9251746831).

Almost surely, 2^18503493661 is an apocalyptic number.

It is an amenable number.

18503493661 is a deficient number, since it is larger than the sum of its proper divisors (1).

18503493661 is an equidigital number, since it uses as much as digits as its factorization.

18503493661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 466560, while the sum is 46.

The spelling of 18503493661 in words is "eighteen billion, five hundred three million, four hundred ninety-three thousand, six hundred sixty-one".