725809 has 4 divisors (see below), whose sum is σ = 829504. Its totient is φ = 622116.

The previous prime is 725807. The next prime is 725827. The reversal of 725809 is 908527.

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.

It is a cyclic number.

It is not a de Polignac number, because 725809 - 2¹ = 725807 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (725801) 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, 51837 + ... + 51850.

It is an arithmetic number, because the mean of its divisors is an integer number (207376).

2⁷²⁵⁸⁰⁹ is an apocalyptic number.

It is an amenable number.

725809 is a deficient number, since it is larger than the sum of its proper divisors (103695).

725809 is a wasteful number, since it uses less digits than its factorization.

725809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 103694.

The product of its (nonzero) digits is 5040, while the sum is 31.

The square root of 725809 is about 851.9442470021. The cubic root of 725809 is about 89.8684910589.

The spelling of 725809 in words is "seven hundred twenty-five thousand, eight hundred nine".