666767977 has 4 divisors (see below), whose sum is σ = 666821716. Its totient is φ = 666714240.

The previous prime is 666767957. The next prime is 666768001. The reversal of 666767977 is 779767666.

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 can be written as a sum of positive squares in 2 ways, for example, as 423906921 + 242861056 = 20589^2 + 15584^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-666767977 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (666767957) 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, 2293 + ... + 36589.

It is an arithmetic number, because the mean of its divisors is an integer number (166705429).

Almost surely, 2^666767977 is an apocalyptic number.

It is an amenable number.

666767977 is a deficient number, since it is larger than the sum of its proper divisors (53739).

666767977 is a wasteful number, since it uses less digits than its factorization.

666767977 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53738.

The product of its digits is 28005264, while the sum is 61.

The square root of 666767977 is about 25821.8507663568. The cubic root of 666767977 is about 873.6247138590.

The spelling of 666767977 in words is "six hundred sixty-six million, seven hundred sixty-seven thousand, nine hundred seventy-seven".