18628009 has 4 divisors (see below), whose sum is σ = 18636804. Its totient is φ = 18619216.

The previous prime is 18628003. The next prime is 18628013. The reversal of 18628009 is 90082681.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 90082681 = 13 ⋅6929437.

It can be written as a sum of positive squares in 2 ways, for example, as 9018009 + 9610000 = 3003^2 + 3100^2 .

It is a cyclic number.

It is not a de Polignac number, because 18628009 - 2⁷ = 18627881 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18628003) 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 in 3 ways as a sum of consecutive naturals, for example, 939 + ... + 6175.

It is an arithmetic number, because the mean of its divisors is an integer number (4659201).

Almost surely, 2^18628009 is an apocalyptic number.

It is an amenable number.

18628009 is a deficient number, since it is larger than the sum of its proper divisors (8795).

18628009 is an equidigital number, since it uses as much as digits as its factorization.

18628009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8794.

The product of its (nonzero) digits is 6912, while the sum is 34.

The square root of 18628009 is about 4316.0177247087. The cubic root of 18628009 is about 265.0872336519.

The spelling of 18628009 in words is "eighteen million, six hundred twenty-eight thousand, nine".