18985717 has 2 divisors, whose sum is σ = 18985718. Its totient is φ = 18985716.

The previous prime is 18985711. The next prime is 18985721. The reversal of 18985717 is 71758981.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18714276 + 271441 = 4326^2 + 521^2 .

It is a cyclic number.

It is not a de Polignac number, because 18985717 - 2³ = 18985709 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18985711) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9492858 + 9492859.

It is an arithmetic number, because the mean of its divisors is an integer number (9492859).

Almost surely, 2^18985717 is an apocalyptic number.

It is an amenable number.

18985717 is a deficient number, since it is larger than the sum of its proper divisors (1).

18985717 is an equidigital number, since it uses as much as digits as its factorization.

18985717 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 141120, while the sum is 46.

The square root of 18985717 is about 4357.2602630552. The cubic root of 18985717 is about 266.7732835827.

The spelling of 18985717 in words is "eighteen million, nine hundred eighty-five thousand, seven hundred seventeen".