665319967 has 4 divisors (see below), whose sum is σ = 716498440. Its totient is φ = 614141496.

The previous prime is 665319947. The next prime is 665320021. The reversal of 665319967 is 769913566.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-665319967 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665319947) 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, 25589217 + ... + 25589242.

It is an arithmetic number, because the mean of its divisors is an integer number (179124610).

Almost surely, 2^665319967 is an apocalyptic number.

665319967 is a deficient number, since it is larger than the sum of its proper divisors (51178473).

665319967 is a wasteful number, since it uses less digits than its factorization.

665319967 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51178472.

The product of its digits is 1837080, while the sum is 52.

The square root of 665319967 is about 25793.7970644107. The cubic root of 665319967 is about 872.9918429495.

The spelling of 665319967 in words is "six hundred sixty-five million, three hundred nineteen thousand, nine hundred sixty-seven".