1720664667173 has 2 divisors, whose sum is σ = 1720664667174. Its totient is φ = 1720664667172.

The previous prime is 1720664667151. The next prime is 1720664667179. The reversal of 1720664667173 is 3717664660271.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1713708773569 + 6955893604 = 1309087^2 + 83402^2 .

It is a cyclic number.

It is not a de Polignac number, because 1720664667173 - 2²⁴ = 1720647889957 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1720664667179) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 860332333586 + 860332333587.

It is an arithmetic number, because the mean of its divisors is an integer number (860332333587).

Almost surely, 2^{1720664667173} is an apocalyptic number.

It is an amenable number.

1720664667173 is a deficient number, since it is larger than the sum of its proper divisors (1).

1720664667173 is an equidigital number, since it uses as much as digits as its factorization.

1720664667173 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10668672, while the sum is 56.

The spelling of 1720664667173 in words is "one trillion, seven hundred twenty billion, six hundred sixty-four million, six hundred sixty-seven thousand, one hundred seventy-three".