1666773649 has 2 divisors, whose sum is σ = 1666773650. Its totient is φ = 1666773648.

The previous prime is 1666773623. The next prime is 1666773677. The reversal of 1666773649 is 9463776661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1320813649 + 345960000 = 36343^2 + 18600^2 .

It is a cyclic number.

It is not a de Polignac number, because 1666773649 - 2¹⁷ = 1666642577 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1666773649.

It is not a weakly prime, because it can be changed into another prime (1666773149) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 833386824 + 833386825.

It is an arithmetic number, because the mean of its divisors is an integer number (833386825).

Almost surely, 2^1666773649 is an apocalyptic number.

It is an amenable number.

1666773649 is a deficient number, since it is larger than the sum of its proper divisors (1).

1666773649 is an equidigital number, since it uses as much as digits as its factorization.

1666773649 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6858432, while the sum is 55.

The square root of 1666773649 is about 40826.1392860016. The cubic root of 1666773649 is about 1185.6564692703.

The spelling of 1666773649 in words is "one billion, six hundred sixty-six million, seven hundred seventy-three thousand, six hundred forty-nine".