871609 has 4 divisors (see below), whose sum is σ = 895204. Its totient is φ = 848016.

The previous prime is 871597. The next prime is 871613. The reversal of 871609 is 906178.

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 313600 + 558009 = 560^2 + 747^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-871609 is a prime.

It is an Ulam number.

It is a Duffinian number.

871609 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (871639) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11742 + ... + 11815.

It is an arithmetic number, because the mean of its divisors is an integer number (223801).

2⁸⁷¹⁶⁰⁹ is an apocalyptic number.

It is an amenable number.

871609 is a deficient number, since it is larger than the sum of its proper divisors (23595).

871609 is a wasteful number, since it uses less digits than its factorization.

871609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23594.

The product of its (nonzero) digits is 3024, while the sum is 31.

The square root of 871609 is about 933.6000214225. The cubic root of 871609 is about 95.5228420458.

It can be divided in two parts, 8 and 71609, that added together give a palindrome (71617).

The spelling of 871609 in words is "eight hundred seventy-one thousand, six hundred nine".