666778873888 has 12 divisors (see below), whose sum is σ = 1312720908030. Its totient is φ = 333389436928.

The previous prime is 666778873853. The next prime is 666778873889. The reversal of 666778873888 is 888378877666.

It can be written as a sum of positive squares in only one way, i.e., 572340667024 + 94438206864 = 756532^2 + 307308^2 .

It is not an unprimeable number, because it can be changed into a prime (666778873889) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10418419873 + ... + 10418419936.

Almost surely, 2^666778873888 is an apocalyptic number.

It is an amenable number.

666778873888 is a deficient number, since it is larger than the sum of its proper divisors (645942034142).

666778873888 is a wasteful number, since it uses less digits than its factorization.

666778873888 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20836839819 (or 20836839811 counting only the distinct ones).

The product of its digits is 7283146752, while the sum is 82.

The spelling of 666778873888 in words is "six hundred sixty-six billion, seven hundred seventy-eight million, eight hundred seventy-three thousand, eight hundred eighty-eight".