723509 has 4 divisors (see below), whose sum is σ = 746880. Its totient is φ = 700140.

The previous prime is 723493. The next prime is 723529. The reversal of 723509 is 905327.

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: 905327 = 107 ⋅8461.

It is a cyclic number.

It is not a de Polignac number, because 723509 - 2⁴ = 723493 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 (723529) 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, 11639 + ... + 11700.

It is an arithmetic number, because the mean of its divisors is an integer number (186720).

2⁷²³⁵⁰⁹ is an apocalyptic number.

It is an amenable number.

723509 is a deficient number, since it is larger than the sum of its proper divisors (23371).

723509 is a wasteful number, since it uses less digits than its factorization.

723509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23370.

The product of its (nonzero) digits is 1890, while the sum is 26.

The square root of 723509 is about 850.5933223345. The cubic root of 723509 is about 89.7734631899.

The spelling of 723509 in words is "seven hundred twenty-three thousand, five hundred nine".