18404987 has 2 divisors, whose sum is σ = 18404988. Its totient is φ = 18404986.

The previous prime is 18404983. The next prime is 18405007. The reversal of 18404987 is 78940481.

It is a happy number.

It is a weak prime.

It is an emirp because it is prime and its reverse (78940481) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18404987 - 2² = 18404983 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18404983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9202493 + 9202494.

It is an arithmetic number, because the mean of its divisors is an integer number (9202494).

Almost surely, 2^18404987 is an apocalyptic number.

18404987 is a deficient number, since it is larger than the sum of its proper divisors (1).

18404987 is an equidigital number, since it uses as much as digits as its factorization.

18404987 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 64512, while the sum is 41.

The square root of 18404987 is about 4290.1033787078. The cubic root of 18404987 is about 264.0250731849.

It can be divided in two parts, 18404 and 987, that added together give a palindrome (19391).

The spelling of 18404987 in words is "eighteen million, four hundred four thousand, nine hundred eighty-seven".