1666975217 has 2 divisors, whose sum is σ = 1666975218. Its totient is φ = 1666975216.

The previous prime is 1666975213. The next prime is 1666975223. The reversal of 1666975217 is 7125796661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1527168241 + 139806976 = 39079^2 + 11824^2 .

It is a cyclic number.

It is not a de Polignac number, because 1666975217 - 2² = 1666975213 is a prime.

It is not a weakly prime, because it can be changed into another prime (1666975213) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 833487608 + 833487609.

It is an arithmetic number, because the mean of its divisors is an integer number (833487609).

Almost surely, 2^1666975217 is an apocalyptic number.

It is an amenable number.

1666975217 is a deficient number, since it is larger than the sum of its proper divisors (1).

1666975217 is an equidigital number, since it uses as much as digits as its factorization.

1666975217 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 952560, while the sum is 50.

The square root of 1666975217 is about 40828.6078258860. The cubic root of 1666975217 is about 1185.7042623564.

The spelling of 1666975217 in words is "one billion, six hundred sixty-six million, nine hundred seventy-five thousand, two hundred seventeen".