665619385 has 4 divisors (see below), whose sum is σ = 798743268. Its totient is φ = 532495504.

The previous prime is 665619371. The next prime is 665619389. The reversal of 665619385 is 583916566.

It is a happy number.

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 93644329 + 571975056 = 9677^2 + 23916^2 .

It is a cyclic number.

It is not a de Polignac number, because 665619385 - 2⁷ = 665619257 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (665619389) 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, 66561934 + ... + 66561943.

It is an arithmetic number, because the mean of its divisors is an integer number (199685817).

Almost surely, 2^665619385 is an apocalyptic number.

It is an amenable number.

665619385 is a deficient number, since it is larger than the sum of its proper divisors (133123883).

665619385 is a wasteful number, since it uses less digits than its factorization.

665619385 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 133123882.

The product of its digits is 1166400, while the sum is 49.

The square root of 665619385 is about 25799.6004814028. The cubic root of 665619385 is about 873.1227825890.

The spelling of 665619385 in words is "six hundred sixty-five million, six hundred nineteen thousand, three hundred eighty-five".