823409 has 4 divisors (see below), whose sum is σ = 826740. Its totient is φ = 820080.

The previous prime is 823399. The next prime is 823421. The reversal of 823409 is 904328.

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 429025 + 394384 = 655^2 + 628^2 .

It is a cyclic number.

It is not a de Polignac number, because 823409 - 2⁸ = 823153 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a zygodrome in base 3.

It is not an unprimeable number, because it can be changed into a prime (823489) 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, 1262 + ... + 1799.

It is an arithmetic number, because the mean of its divisors is an integer number (206685).

2⁸²³⁴⁰⁹ is an apocalyptic number.

It is an amenable number.

823409 is a deficient number, since it is larger than the sum of its proper divisors (3331).

823409 is a wasteful number, since it uses less digits than its factorization.

823409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3330.

The product of its (nonzero) digits is 1728, while the sum is 26.

The square root of 823409 is about 907.4188668966. The cubic root of 823409 is about 93.7285438305.

The spelling of 823409 in words is "eight hundred twenty-three thousand, four hundred nine".