725509 has 4 divisors (see below), whose sum is σ = 768204. Its totient is φ = 682816.

The previous prime is 725507. The next prime is 725519. The reversal of 725509 is 905527.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 905527 = 7 ⋅129361.

It can be written as a sum of positive squares in 2 ways, for example, as 497025 + 228484 = 705^2 + 478^2 .

It is a cyclic number.

It is not a de Polignac number, because 725509 - 2¹ = 725507 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (725507) 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, 21322 + ... + 21355.

It is an arithmetic number, because the mean of its divisors is an integer number (192051).

2⁷²⁵⁵⁰⁹ is an apocalyptic number.

It is an amenable number.

725509 is a deficient number, since it is larger than the sum of its proper divisors (42695).

725509 is a wasteful number, since it uses less digits than its factorization.

725509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42694.

The product of its (nonzero) digits is 3150, while the sum is 28.

The square root of 725509 is about 851.7681609452. The cubic root of 725509 is about 89.8561075151.

The spelling of 725509 in words is "seven hundred twenty-five thousand, five hundred nine".