665949371 has 4 divisors (see below), whose sum is σ = 666018672. Its totient is φ = 665880072.

The previous prime is 665949311. The next prime is 665949397. The reversal of 665949371 is 173949566.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 665949371 - 2⁶ = 665949307 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (665949311) 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, 17360 + ... + 40413.

It is an arithmetic number, because the mean of its divisors is an integer number (166504668).

Almost surely, 2^665949371 is an apocalyptic number.

665949371 is a deficient number, since it is larger than the sum of its proper divisors (69301).

665949371 is a wasteful number, since it uses less digits than its factorization.

665949371 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69300.

The product of its digits is 1224720, while the sum is 50.

The square root of 665949371 is about 25805.9948655346. The cubic root of 665949371 is about 873.2670445610.

The spelling of 665949371 in words is "six hundred sixty-five million, nine hundred forty-nine thousand, three hundred seventy-one".