668577775866 has 192 divisors, whose sum is σ = 1854003603456. Its totient is φ = 155965305600.

The previous prime is 668577775807. The next prime is 668577775889.

668577775866 is nontrivially palindromic in base 10.

It is a Harshad number since it is a multiple of its sum of digits (78).

It is a junction number, because it is equal to n+sod(n) for n = 668577775791 and 668577775800.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 2773171 + ... + 3004601.

It is an arithmetic number, because the mean of its divisors is an integer number (9656268768).

Almost surely, 2^668577775866 is an apocalyptic number.

668577775866 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 668577775866, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (927001801728).

668577775866 is an abundant number, since it is smaller than the sum of its proper divisors (1185425827590).

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

668577775866 is a wasteful number, since it uses less digits than its factorization.

668577775866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 231517 (or 231504 counting only the distinct ones).

The product of its digits is 4978713600, while the sum is 78.

The spelling of 668577775866 in words is "six hundred sixty-eight billion, five hundred seventy-seven million, seven hundred seventy-five thousand, eight hundred sixty-six".