66565859994 has 16 divisors (see below), whose sum is σ = 147924133440. Its totient is φ = 22188619980.

The previous prime is 66565859993. The next prime is 66565860013. The reversal of 66565859994 is 49995856566.

66565859994 is a `hidden beast` number, since 6 + 6 + 565 + 8 + 59 + 9 + 9 + 4 = 666.

It is not an unprimeable number, because it can be changed into a prime (66565859993) 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, 616350502 + ... + 616350609.

It is an arithmetic number, because the mean of its divisors is an integer number (9245258340).

Almost surely, 2^66565859994 is an apocalyptic number.

66565859994 is an abundant number, since it is smaller than the sum of its proper divisors (81358273446).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66565859994 is a wasteful number, since it uses less digits than its factorization.

66565859994 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1232701122 (or 1232701116 counting only the distinct ones).

The product of its digits is 629856000, while the sum is 72.

The spelling of 66565859994 in words is "sixty-six billion, five hundred sixty-five million, eight hundred fifty-nine thousand, nine hundred ninety-four".