666676765 has 4 divisors (see below), whose sum is σ = 800012124. Its totient is φ = 533341408.

The previous prime is 666676741. The next prime is 666676783. The reversal of 666676765 is 567676666.

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

It can be written as a sum of positive squares in 2 ways, for example, as 167288356 + 499388409 = 12934^2 + 22347^2 .

It is a cyclic number.

It is not a de Polignac number, because 666676765 - 2²¹ = 664579613 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66667672 + ... + 66667681.

It is an arithmetic number, because the mean of its divisors is an integer number (200003031).

Almost surely, 2^666676765 is an apocalyptic number.

It is an amenable number.

666676765 is a deficient number, since it is larger than the sum of its proper divisors (133335359).

666676765 is a wasteful number, since it uses less digits than its factorization.

666676765 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133335358.

The product of its digits is 11430720, while the sum is 55.

The square root of 666676765 is about 25820.0845273597. The cubic root of 666676765 is about 873.5848755674.

Subtracting from 666676765 its reverse (567676666), we obtain a palindrome (99000099).

The spelling of 666676765 in words is "six hundred sixty-six million, six hundred seventy-six thousand, seven hundred sixty-five".