667808965 has 8 divisors (see below), whose sum is σ = 801617400. Its totient is φ = 534082752.

The previous prime is 667808951. The next prime is 667808969. The reversal of 667808965 is 569808766.

It is a happy number.

It is a Cunningham number, because it is equal to 25842²+1.

It can be written as a sum of positive squares in 4 ways, for example, as 1 + 667808964 = 1^2 + 25842^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 667808965 - 2¹¹ = 667806917 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (667808969) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 990 + ... + 36559.

It is an arithmetic number, because the mean of its divisors is an integer number (100202175).

Almost surely, 2^667808965 is an apocalyptic number.

It is an amenable number.

667808965 is a deficient number, since it is larger than the sum of its proper divisors (133808435).

667808965 is a wasteful number, since it uses less digits than its factorization.

667808965 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41111.

The product of its (nonzero) digits is 4354560, while the sum is 55.

The square root of 667808965 is about 25842.0000193483. Note that the first 4 decimals coincide. The cubic root of 667808965 is about 874.0791247898.

The spelling of 667808965 in words is "six hundred sixty-seven million, eight hundred eight thousand, nine hundred sixty-five".