666665716 has 24 divisors (see below), whose sum is σ = 1178526440. Its totient is φ = 329961600.

The previous prime is 666665689. The next prime is 666665723. The reversal of 666665716 is 617566666.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 1232100 + 665433616 = 1110^2 + 25796^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 666665716.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 163786 + ... + 167806.

Almost surely, 2^666665716 is an apocalyptic number.

It is an amenable number.

666665716 is a deficient number, since it is larger than the sum of its proper divisors (511860724).

666665716 is a wasteful number, since it uses less digits than its factorization.

666665716 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4435 (or 4433 counting only the distinct ones).

The product of its digits is 1632960, while the sum is 49.

The square root of 666665716 is about 25819.8705651287. The cubic root of 666665716 is about 873.5800494942.

The spelling of 666665716 in words is "six hundred sixty-six million, six hundred sixty-five thousand, seven hundred sixteen".