669778099649 has 2 divisors, whose sum is σ = 669778099650. Its totient is φ = 669778099648.

The previous prime is 669778099607. The next prime is 669778099663. The reversal of 669778099649 is 946990877966.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 577964857600 + 91813242049 = 760240^2 + 303007^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-669778099649 is a prime.

It is not a weakly prime, because it can be changed into another prime (669778092649) 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, 334889049824 + 334889049825.

It is an arithmetic number, because the mean of its divisors is an integer number (334889049825).

Almost surely, 2^669778099649 is an apocalyptic number.

It is an amenable number.

669778099649 is a deficient number, since it is larger than the sum of its proper divisors (1).

669778099649 is an equidigital number, since it uses as much as digits as its factorization.

669778099649 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2222131968, while the sum is 80.

The spelling of 669778099649 in words is "six hundred sixty-nine billion, seven hundred seventy-eight million, ninety-nine thousand, six hundred forty-nine".