18516857503 has 4 divisors (see below), whose sum is σ = 19321938288. Its totient is φ = 17711776720.

The previous prime is 18516857461. The next prime is 18516857509. The reversal of 18516857503 is 30575861581.

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 18516857503 - 2⁹ = 18516856991 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 (18516857509) 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, 402540358 + ... + 402540403.

It is an arithmetic number, because the mean of its divisors is an integer number (4830484572).

Almost surely, 2^18516857503 is an apocalyptic number.

18516857503 is a deficient number, since it is larger than the sum of its proper divisors (805080785).

18516857503 is an equidigital number, since it uses as much as digits as its factorization.

18516857503 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 805080784.

The product of its (nonzero) digits is 1008000, while the sum is 49.

The spelling of 18516857503 in words is "eighteen billion, five hundred sixteen million, eight hundred fifty-seven thousand, five hundred three".