685161217 has 8 divisors (see below), whose sum is σ = 781270056. Its totient is φ = 595252992.

The previous prime is 685161203. The next prime is 685161241. The reversal of 685161217 is 712161586.

It can be written as a sum of positive squares in 4 ways, for example, as 2070721 + 683090496 = 1439^2 + 26136^2 .

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 685161217 - 2²⁷ = 550943489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (685161517) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1549918 + ... + 1550359.

It is an arithmetic number, because the mean of its divisors is an integer number (97658757).

Almost surely, 2^685161217 is an apocalyptic number.

It is an amenable number.

685161217 is a deficient number, since it is larger than the sum of its proper divisors (96108839).

685161217 is a wasteful number, since it uses less digits than its factorization.

685161217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3100307.

The product of its digits is 20160, while the sum is 37.

The square root of 685161217 is about 26175.5843678799. The cubic root of 685161217 is about 881.5851324186.

It can be divided in two parts, 68 and 5161217, that multiplied together give a square (350962756 = 18734²).

The spelling of 685161217 in words is "six hundred eighty-five million, one hundred sixty-one thousand, two hundred seventeen".