918409 has 4 divisors (see below), whose sum is σ = 922320. Its totient is φ = 914500.

The previous prime is 918397. The next prime is 918431. The reversal of 918409 is 904819.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 904819 = 181 ⋅4999.

It is a cyclic number.

It is not a de Polignac number, because 918409 - 2¹¹ = 916361 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (918439) 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, 1579 + ... + 2080.

It is an arithmetic number, because the mean of its divisors is an integer number (230580).

2⁹¹⁸⁴⁰⁹ is an apocalyptic number.

It is an amenable number.

918409 is a deficient number, since it is larger than the sum of its proper divisors (3911).

918409 is a wasteful number, since it uses less digits than its factorization.

918409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3910.

The product of its (nonzero) digits is 2592, while the sum is 31.

The square root of 918409 is about 958.3365797046. The cubic root of 918409 is about 97.2027854599.

The spelling of 918409 in words is "nine hundred eighteen thousand, four hundred nine".