18509966 has 4 divisors (see below), whose sum is σ = 27764952. Its totient is φ = 9254982.

The previous prime is 18509941. The next prime is 18509977. The reversal of 18509966 is 66990581.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4627490 + ... + 4627493.

It is an arithmetic number, because the mean of its divisors is an integer number (6941238).

Almost surely, 2^18509966 is an apocalyptic number.

18509966 is a deficient number, since it is larger than the sum of its proper divisors (9254986).

18509966 is an equidigital number, since it uses as much as digits as its factorization.

18509966 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9254985.

The product of its (nonzero) digits is 116640, while the sum is 44.

The square root of 18509966 is about 4302.3210015060. The cubic root of 18509966 is about 264.5261068924.

The spelling of 18509966 in words is "eighteen million, five hundred nine thousand, nine hundred sixty-six".