685240217 has 8 divisors (see below), whose sum is σ = 725355840. Its totient is φ = 646223760.

The previous prime is 685240207. The next prime is 685240223. The reversal of 685240217 is 712042586.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 685240217 - 2⁴ = 685240201 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (685240207) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 273509 + ... + 276002.

It is an arithmetic number, because the mean of its divisors is an integer number (90669480).

Almost surely, 2^685240217 is an apocalyptic number.

It is an amenable number.

685240217 is a deficient number, since it is larger than the sum of its proper divisors (40115623).

685240217 is a wasteful number, since it uses less digits than its factorization.

685240217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 549583.

The product of its (nonzero) digits is 26880, while the sum is 35.

The square root of 685240217 is about 26177.0933642374. The cubic root of 685240217 is about 881.6190137627.

The spelling of 685240217 in words is "six hundred eighty-five million, two hundred forty thousand, two hundred seventeen".