18987499 has 2 divisors, whose sum is σ = 18987500. Its totient is φ = 18987498.

The previous prime is 18987497. The next prime is 18987511. The reversal of 18987499 is 99478981.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 18987499 - 2¹ = 18987497 is a prime.

Together with 18987497, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (18987491) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9493749 + 9493750.

It is an arithmetic number, because the mean of its divisors is an integer number (9493750).

Almost surely, 2^18987499 is an apocalyptic number.

18987499 is a deficient number, since it is larger than the sum of its proper divisors (1).

18987499 is an equidigital number, since it uses as much as digits as its factorization.

18987499 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1306368, while the sum is 55.

The square root of 18987499 is about 4357.4647445504. The cubic root of 18987499 is about 266.7816297712.

The spelling of 18987499 in words is "eighteen million, nine hundred eighty-seven thousand, four hundred ninety-nine".