666523187778 has 32 divisors (see below), whose sum is σ = 1524498048000. Its totient is φ = 190308137040.

The previous prime is 666523187777. The next prime is 666523187791. The reversal of 666523187778 is 877781325666.

666523187778 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not an unprimeable number, because it can be changed into a prime (666523187773) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5230438 + ... + 5356353.

It is an arithmetic number, because the mean of its divisors is an integer number (47640564000).

Almost surely, 2^666523187778 is an apocalyptic number.

666523187778 is an abundant number, since it is smaller than the sum of its proper divisors (857974860222).

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

666523187778 is a wasteful number, since it uses less digits than its factorization.

666523187778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10588302.

The product of its digits is 142248960, while the sum is 66.

The spelling of 666523187778 in words is "six hundred sixty-six billion, five hundred twenty-three million, one hundred eighty-seven thousand, seven hundred seventy-eight".