665605667 has 4 divisors (see below), whose sum is σ = 667581096. Its totient is φ = 663630240.

The previous prime is 665605639. The next prime is 665605693. The reversal of 665605667 is 766506566.

665605667 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is not a de Polignac number, because 665605667 - 2⁸ = 665605411 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (665605637) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 987209 + ... + 987882.

It is an arithmetic number, because the mean of its divisors is an integer number (166895274).

Almost surely, 2^665605667 is an apocalyptic number.

665605667 is a deficient number, since it is larger than the sum of its proper divisors (1975429).

665605667 is a wasteful number, since it uses less digits than its factorization.

665605667 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1975428.

The product of its (nonzero) digits is 1360800, while the sum is 47.

The square root of 665605667 is about 25799.3346232030. The cubic root of 665605667 is about 873.1167843759.

It can be divided in two parts, 66560 and 5667, that added together give a palindrome (72227).

The spelling of 665605667 in words is "six hundred sixty-five million, six hundred five thousand, six hundred sixty-seven".