1666666693 has 2 divisors, whose sum is σ = 1666666694. Its totient is φ = 1666666692.

The previous prime is 1666666679. The next prime is 1666666711. The reversal of 1666666693 is 3966666661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1369518049 + 297148644 = 37007^2 + 17238^2 .

It is a cyclic number.

It is not a de Polignac number, because 1666666693 - 2¹⁷ = 1666535621 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1666666613) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 833333346 + 833333347.

It is an arithmetic number, because the mean of its divisors is an integer number (833333347).

Almost surely, 2^1666666693 is an apocalyptic number.

It is an amenable number.

1666666693 is a deficient number, since it is larger than the sum of its proper divisors (1).

1666666693 is an equidigital number, since it uses as much as digits as its factorization.

1666666693 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7558272, while the sum is 55.

The square root of 1666666693 is about 40824.8293689024. The cubic root of 1666666693 is about 1185.6311077410.

The spelling of 1666666693 in words is "one billion, six hundred sixty-six million, six hundred sixty-six thousand, six hundred ninety-three".