1686172723217 has 2 divisors, whose sum is σ = 1686172723218. Its totient is φ = 1686172723216.

The previous prime is 1686172723187. The next prime is 1686172723223. The reversal of 1686172723217 is 7123272716861.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1665521883601 + 20650839616 = 1290551^2 + 143704^2 .

It is a cyclic number.

It is not a de Polignac number, because 1686172723217 - 2³⁶ = 1617453246481 is a prime.

It is not a weakly prime, because it can be changed into another prime (1686172323217) 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 as a sum of consecutive naturals, namely, 843086361608 + 843086361609.

It is an arithmetic number, because the mean of its divisors is an integer number (843086361609).

Almost surely, 2^{1686172723217} is an apocalyptic number.

It is an amenable number.

1686172723217 is a deficient number, since it is larger than the sum of its proper divisors (1).

1686172723217 is an equidigital number, since it uses as much as digits as its factorization.

1686172723217 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2370816, while the sum is 53.

The spelling of 1686172723217 in words is "one trillion, six hundred eighty-six billion, one hundred seventy-two million, seven hundred twenty-three thousand, two hundred seventeen".