666149009 has 2 divisors, whose sum is σ = 666149010. Its totient is φ = 666149008.

The previous prime is 666148993. The next prime is 666149039. The reversal of 666149009 is 900941666.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 494617600 + 171531409 = 22240^2 + 13097^2 .

It is a cyclic number.

It is not a de Polignac number, because 666149009 - 2⁴ = 666148993 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (666149039) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333074504 + 333074505.

It is an arithmetic number, because the mean of its divisors is an integer number (333074505).

Almost surely, 2^666149009 is an apocalyptic number.

It is an amenable number.

666149009 is a deficient number, since it is larger than the sum of its proper divisors (1).

666149009 is an equidigital number, since it uses as much as digits as its factorization.

666149009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 69984, while the sum is 41.

The square root of 666149009 is about 25809.8626303977. The cubic root of 666149009 is about 873.3542983753.

The spelling of 666149009 in words is "six hundred sixty-six million, one hundred forty-nine thousand, nine".