18240409 has 8 divisors (see below), whose sum is σ = 19933920. Its totient is φ = 16552800.

The previous prime is 18240407. The next prime is 18240413. The reversal of 18240409 is 90404281.

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

It is not a de Polignac number, because 18240409 - 2¹ = 18240407 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18240401) 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, 7282 + ... + 9460.

It is an arithmetic number, because the mean of its divisors is an integer number (2491740).

Almost surely, 2^18240409 is an apocalyptic number.

It is an amenable number.

18240409 is a deficient number, since it is larger than the sum of its proper divisors (1693511).

18240409 is a wasteful number, since it uses less digits than its factorization.

18240409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2951.

The product of its (nonzero) digits is 2304, while the sum is 28.

The square root of 18240409 is about 4270.8791834937. The cubic root of 18240409 is about 263.2357421135.

The spelling of 18240409 in words is "eighteen million, two hundred forty thousand, four hundred nine".