666746849 has 2 divisors, whose sum is σ = 666746850. Its totient is φ = 666746848.

The previous prime is 666746833. The next prime is 666746867. The reversal of 666746849 is 948647666.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 633025600 + 33721249 = 25160^2 + 5807^2 .

It is a cyclic number.

It is not a de Polignac number, because 666746849 - 2⁴ = 666746833 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 666746794 and 666746803.

It is not a weakly prime, because it can be changed into another prime (666746809) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333373424 + 333373425.

It is an arithmetic number, because the mean of its divisors is an integer number (333373425).

Almost surely, 2^666746849 is an apocalyptic number.

It is an amenable number.

666746849 is a deficient number, since it is larger than the sum of its proper divisors (1).

666746849 is an equidigital number, since it uses as much as digits as its factorization.

666746849 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10450944, while the sum is 56.

The square root of 666746849 is about 25821.4416522393. The cubic root of 666746849 is about 873.6154861923.

The spelling of 666746849 in words is "six hundred sixty-six million, seven hundred forty-six thousand, eight hundred forty-nine".