668618449 has 4 divisors (see below), whose sum is σ = 707948964. Its totient is φ = 629287936.

The previous prime is 668618413. The next prime is 668618459. The reversal of 668618449 is 944816866.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 317730625 + 350887824 = 17825^2 + 18732^2 .

It is a cyclic number.

It is not a de Polignac number, because 668618449 - 2¹⁷ = 668487377 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 668618396 and 668618405.

It is not an unprimeable number, because it can be changed into a prime (668618459) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19665232 + ... + 19665265.

It is an arithmetic number, because the mean of its divisors is an integer number (176987241).

Almost surely, 2^668618449 is an apocalyptic number.

It is an amenable number.

668618449 is a deficient number, since it is larger than the sum of its proper divisors (39330515).

668618449 is a wasteful number, since it uses less digits than its factorization.

668618449 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39330514.

The product of its digits is 1990656, while the sum is 52.

The square root of 668618449 is about 25857.6574538375. The cubic root of 668618449 is about 874.4321535795.

The spelling of 668618449 in words is "six hundred sixty-eight million, six hundred eighteen thousand, four hundred forty-nine".