168721317 has 12 divisors (see below), whose sum is σ = 245866764. Its totient is φ = 111484800.

The previous prime is 168721291. The next prime is 168721337. The reversal of 168721317 is 713127861.

It can be written as a sum of positive squares in 2 ways, for example, as 15729156 + 152992161 = 3966^2 + 12369^2 .

It is not a de Polignac number, because 168721317 - 2¹¹ = 168719269 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (168721337) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 81934 + ... + 83967.

It is an arithmetic number, because the mean of its divisors is an integer number (20488897).

Almost surely, 2^168721317 is an apocalyptic number.

It is an amenable number.

168721317 is a deficient number, since it is larger than the sum of its proper divisors (77145447).

168721317 is a wasteful number, since it uses less digits than its factorization.

168721317 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 166020 (or 166017 counting only the distinct ones).

The product of its digits is 14112, while the sum is 36.

The square root of 168721317 is about 12989.2770006648. The cubic root of 168721317 is about 552.5734136663.

The spelling of 168721317 in words is "one hundred sixty-eight million, seven hundred twenty-one thousand, three hundred seventeen".