18400609 has 4 divisors (see below), whose sum is σ = 18590404. Its totient is φ = 18210816.

The previous prime is 18400597. The next prime is 18400631. The reversal of 18400609 is 90600481.

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

It can be written as a sum of positive squares in 2 ways, for example, as 10419984 + 7980625 = 3228^2 + 2825^2 .

It is a cyclic number.

It is not a de Polignac number, because 18400609 - 2⁹ = 18400097 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18400909) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 94752 + ... + 94945.

It is an arithmetic number, because the mean of its divisors is an integer number (4647601).

Almost surely, 2^18400609 is an apocalyptic number.

It is an amenable number.

18400609 is a deficient number, since it is larger than the sum of its proper divisors (189795).

18400609 is an equidigital number, since it uses as much as digits as its factorization.

18400609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 189794.

The product of its (nonzero) digits is 1728, while the sum is 28.

The square root of 18400609 is about 4289.5931042466. The cubic root of 18400609 is about 264.0041369493.

The spelling of 18400609 in words is "eighteen million, four hundred thousand, six hundred nine".