18985387 has 2 divisors, whose sum is σ = 18985388. Its totient is φ = 18985386.

The previous prime is 18985367. The next prime is 18985397. The reversal of 18985387 is 78358981.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 18985387 - 2⁷ = 18985259 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18985387.

It is not a weakly prime, because it can be changed into another prime (18985367) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9492693 + 9492694.

It is an arithmetic number, because the mean of its divisors is an integer number (9492694).

Almost surely, 2^18985387 is an apocalyptic number.

18985387 is a deficient number, since it is larger than the sum of its proper divisors (1).

18985387 is an equidigital number, since it uses as much as digits as its factorization.

18985387 is an evil number, because the sum of its binary digits is even.

The product of its digits is 483840, while the sum is 49.

The square root of 18985387 is about 4357.2223950586. Note that the first 3 decimals coincide. The cubic root of 18985387 is about 266.7717379349.

The spelling of 18985387 in words is "eighteen million, nine hundred eighty-five thousand, three hundred eighty-seven".