18406987 has 2 divisors, whose sum is σ = 18406988. Its totient is φ = 18406986.

The previous prime is 18406981. The next prime is 18407003. The reversal of 18406987 is 78960481.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 18406987 - 2³ = 18406979 is a prime.

It is not a weakly prime, because it can be changed into another prime (18406981) 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, 9203493 + 9203494.

It is an arithmetic number, because the mean of its divisors is an integer number (9203494).

Almost surely, 2^18406987 is an apocalyptic number.

18406987 is a deficient number, since it is larger than the sum of its proper divisors (1).

18406987 is an equidigital number, since it uses as much as digits as its factorization.

18406987 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 96768, while the sum is 43.

The square root of 18406987 is about 4290.3364669918. The cubic root of 18406987 is about 264.0346363723.

The spelling of 18406987 in words is "eighteen million, four hundred six thousand, nine hundred eighty-seven".