18705887 has 2 divisors, whose sum is σ = 18705888. Its totient is φ = 18705886.

The previous prime is 18705871. The next prime is 18705893. The reversal of 18705887 is 78850781.

It is a strong prime.

It is an emirp because it is prime and its reverse (78850781) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18705887 - 2⁴ = 18705871 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18705587) 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, 9352943 + 9352944.

It is an arithmetic number, because the mean of its divisors is an integer number (9352944).

Almost surely, 2^18705887 is an apocalyptic number.

18705887 is a deficient number, since it is larger than the sum of its proper divisors (1).

18705887 is an equidigital number, since it uses as much as digits as its factorization.

18705887 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 125440, while the sum is 44.

The square root of 18705887 is about 4325.0302889113. The cubic root of 18705887 is about 265.4561362155.

The spelling of 18705887 in words is "eighteen million, seven hundred five thousand, eight hundred eighty-seven".