666806806800 has 300 divisors, whose sum is σ = 2428842178576. Its totient is φ = 175160620800.

The previous prime is 666806806759. The next prime is 666806806801. The reversal of 666806806800 is 8608608666.

It is a tau number, because it is divible by the number of its divisors (300).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (666806806801) by changing a digit.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 2017215 + ... + 2324385.

Almost surely, 2^666806806800 is an apocalyptic number.

666806806800 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 666806806800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1214421089288).

666806806800 is an abundant number, since it is smaller than the sum of its proper divisors (1762035371776).

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

666806806800 is a wasteful number, since it uses less digits than its factorization.

666806806800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 307268 (or 307248 counting only the distinct ones).

The product of its (nonzero) digits is 3981312, while the sum is 54.

The spelling of 666806806800 in words is "six hundred sixty-six billion, eight hundred six million, eight hundred six thousand, eight hundred".