872509 has 4 divisors (see below), whose sum is σ = 951840. Its totient is φ = 793180.

The previous prime is 872479. The next prime is 872533. The reversal of 872509 is 905278.

872509 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 872509 - 2⁵ = 872477 is a prime.

It is a super-2 number, since 2×872509² = 1522543910162, which contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

872509 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (872549) 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, 39649 + ... + 39670.

It is an arithmetic number, because the mean of its divisors is an integer number (237960).

2⁸⁷²⁵⁰⁹ is an apocalyptic number.

It is an amenable number.

872509 is a deficient number, since it is larger than the sum of its proper divisors (79331).

872509 is a wasteful number, since it uses less digits than its factorization.

872509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79330.

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

The square root of 872509 is about 934.0819021906. The cubic root of 872509 is about 95.5557088414. Note that the first 3 decimals are identical.

The spelling of 872509 in words is "eight hundred seventy-two thousand, five hundred nine".