825409 has 4 divisors (see below), whose sum is σ = 888916. Its totient is φ = 761904.

The previous prime is 825403. The next prime is 825413. The reversal of 825409 is 904528.

It is a happy number.

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 65025 + 760384 = 255^2 + 872^2 .

It is not a de Polignac number, because 825409 - 2⁷ = 825281 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 16.

It is not an unprimeable number, because it can be changed into a prime (825403) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 31734 + ... + 31759.

It is an arithmetic number, because the mean of its divisors is an integer number (222229).

2⁸²⁵⁴⁰⁹ is an apocalyptic number.

It is an amenable number.

825409 is a deficient number, since it is larger than the sum of its proper divisors (63507).

825409 is a wasteful number, since it uses less digits than its factorization.

825409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63506.

The product of its (nonzero) digits is 2880, while the sum is 28.

The square root of 825409 is about 908.5202254215. The cubic root of 825409 is about 93.8043690559.

The spelling of 825409 in words is "eight hundred twenty-five thousand, four hundred nine".