665647379 has 2 divisors, whose sum is σ = 665647380. Its totient is φ = 665647378.

The previous prime is 665647373. The next prime is 665647399. The reversal of 665647379 is 973746566.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 665647379 - 2⁴ = 665647363 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 665647379.

It is not a weakly prime, because it can be changed into another prime (665647373) 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 as a sum of consecutive naturals, namely, 332823689 + 332823690.

It is an arithmetic number, because the mean of its divisors is an integer number (332823690).

Almost surely, 2^665647379 is an apocalyptic number.

665647379 is a deficient number, since it is larger than the sum of its proper divisors (1).

665647379 is an equidigital number, since it uses as much as digits as its factorization.

665647379 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5715360, while the sum is 53.

The square root of 665647379 is about 25800.1430034797. The cubic root of 665647379 is about 873.1350227456.

The spelling of 665647379 in words is "six hundred sixty-five million, six hundred forty-seven thousand, three hundred seventy-nine".