685217 has 4 divisors (see below), whose sum is σ = 737940. Its totient is φ = 632496.

The previous prime is 685199. The next prime is 685231. The reversal of 685217 is 712586.

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 59536 + 625681 = 244^2 + 791^2 .

It is a cyclic number.

It is not a de Polignac number, because 685217 - 2⁸ = 684961 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 685217.

It is not an unprimeable number, because it can be changed into a prime (685247) 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, 26342 + ... + 26367.

It is an arithmetic number, because the mean of its divisors is an integer number (184485).

2⁶⁸⁵²¹⁷ is an apocalyptic number.

It is an amenable number.

685217 is a deficient number, since it is larger than the sum of its proper divisors (52723).

685217 is a wasteful number, since it uses less digits than its factorization.

685217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52722.

The product of its digits is 3360, while the sum is 29.

The square root of 685217 is about 827.7783519759. The cubic root of 685217 is about 88.1609056778.

The spelling of 685217 in words is "six hundred eighty-five thousand, two hundred seventeen".