660865567 has 4 divisors (see below), whose sum is σ = 660988720. Its totient is φ = 660742416.

The previous prime is 660865561. The next prime is 660865591. The reversal of 660865567 is 765568066.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 765568066 = 2 ⋅382784033.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-660865567 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 660865567.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (660865561) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 53142 + ... + 64387.

It is an arithmetic number, because the mean of its divisors is an integer number (165247180).

Almost surely, 2^660865567 is an apocalyptic number.

660865567 is a deficient number, since it is larger than the sum of its proper divisors (123153).

660865567 is a wasteful number, since it uses less digits than its factorization.

660865567 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 123152.

The product of its (nonzero) digits is 1814400, while the sum is 49.

The square root of 660865567 is about 25707.3057125791. The cubic root of 660865567 is about 871.0392157298.

The spelling of 660865567 in words is "six hundred sixty million, eight hundred sixty-five thousand, five hundred sixty-seven".