18225809 has 8 divisors (see below), whose sum is σ = 21140928. Its totient is φ = 15388560.

The previous prime is 18225791. The next prime is 18225811. The reversal of 18225809 is 90852281.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 18225809 - 2²⁰ = 17177233 is a prime.

It is a super-2 number, since 2×18225809² = 664360227408962, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18225839) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18962 + ... + 19899.

It is an arithmetic number, because the mean of its divisors is an integer number (2642616).

Almost surely, 2^18225809 is an apocalyptic number.

It is an amenable number.

18225809 is a deficient number, since it is larger than the sum of its proper divisors (2915119).

18225809 is an equidigital number, since it uses as much as digits as its factorization.

18225809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38935.

The product of its (nonzero) digits is 11520, while the sum is 35.

The square root of 18225809 is about 4269.1695913843. The cubic root of 18225809 is about 263.1654902587.

The spelling of 18225809 in words is "eighteen million, two hundred twenty-five thousand, eight hundred nine".