666750057666 has 384 divisors, whose sum is σ = 1802010322944. Its totient is φ = 162285742080.

The previous prime is 666750057661. The next prime is 666750057667.

666750057666 is nontrivially palindromic in base 10.

It is a super-2 number, since 2×666750057666² (a number of 24 digits) contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (666750057661) by changing a digit.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 1679470980 + ... + 1679471376.

It is an arithmetic number, because the mean of its divisors is an integer number (4692735216).

Almost surely, 2^666750057666 is an apocalyptic number.

666750057666 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 666750057666, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (901005161472).

666750057666 is an abundant number, since it is smaller than the sum of its proper divisors (1135260265278).

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

666750057666 is a wasteful number, since it uses less digits than its factorization.

666750057666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 854 (or 847 counting only the distinct ones).

The product of its (nonzero) digits is 57153600, while the sum is 60.

The spelling of 666750057666 in words is "six hundred sixty-six billion, seven hundred fifty million, fifty-seven thousand, six hundred sixty-six".