669949949 has 2 divisors, whose sum is σ = 669949950. Its totient is φ = 669949948.

The previous prime is 669949927. The next prime is 669949979. The reversal of 669949949 is 949949966.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 667447225 + 2502724 = 25835^2 + 1582^2 .

It is a cyclic number.

It is not a de Polignac number, because 669949949 - 2²⁸ = 401514493 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (669949979) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334974974 + 334974975.

It is an arithmetic number, because the mean of its divisors is an integer number (334974975).

Almost surely, 2^669949949 is an apocalyptic number.

It is an amenable number.

669949949 is a deficient number, since it is larger than the sum of its proper divisors (1).

669949949 is an equidigital number, since it uses as much as digits as its factorization.

669949949 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 34012224, while the sum is 65.

The square root of 669949949 is about 25883.3913736203. The cubic root of 669949949 is about 875.0122225231.

The spelling of 669949949 in words is "six hundred sixty-nine million, nine hundred forty-nine thousand, nine hundred forty-nine".