870209 has 4 divisors (see below), whose sum is σ = 872916. Its totient is φ = 867504.

The previous prime is 870197. The next prime is 870211. The reversal of 870209 is 902078.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 902078 = 2 ⋅451039.

It can be written as a sum of positive squares in 2 ways, for example, as 384400 + 485809 = 620^2 + 697^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-870209 is a prime.

It is a Duffinian number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 870209.

It is not an unprimeable number, because it can be changed into a prime (870229) 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, 794 + ... + 1539.

It is an arithmetic number, because the mean of its divisors is an integer number (218229).

2⁸⁷⁰²⁰⁹ is an apocalyptic number.

It is an amenable number.

870209 is a deficient number, since it is larger than the sum of its proper divisors (2707).

870209 is a wasteful number, since it uses less digits than its factorization.

870209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2706.

The product of its (nonzero) digits is 1008, while the sum is 26.

The square root of 870209 is about 932.8499343410. The cubic root of 870209 is about 95.4716709190.

The spelling of 870209 in words is "eight hundred seventy thousand, two hundred nine".