1666944317 has 2 divisors, whose sum is σ = 1666944318. Its totient is φ = 1666944316.

The previous prime is 1666944263. The next prime is 1666944329. The reversal of 1666944317 is 7134496661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1665537721 + 1406596 = 40811^2 + 1186^2 .

It is a cyclic number.

It is not a de Polignac number, because 1666944317 - 2¹⁰ = 1666943293 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1666944337) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 833472158 + 833472159.

It is an arithmetic number, because the mean of its divisors is an integer number (833472159).

Almost surely, 2^1666944317 is an apocalyptic number.

It is an amenable number.

1666944317 is a deficient number, since it is larger than the sum of its proper divisors (1).

1666944317 is an equidigital number, since it uses as much as digits as its factorization.

1666944317 is an evil number, because the sum of its binary digits is even.

The product of its digits is 653184, while the sum is 47.

The square root of 1666944317 is about 40828.2294129932. The cubic root of 1666944317 is about 1185.6969360151.

The spelling of 1666944317 in words is "one billion, six hundred sixty-six million, nine hundred forty-four thousand, three hundred seventeen".