666777800 has 96 divisors (see below), whose sum is σ = 1676845800. Its totient is φ = 245114880.

The previous prime is 666777799. The next prime is 666777803. The reversal of 666777800 is 8777666.

It is a happy number.

It can be written as a sum of positive squares in 12 ways, for example, as 2116 + 666775684 = 46^2 + 25822^2 .

It is a super-3 number, since 3×666777800³ (a number of 27 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (666777803) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 823796 + ... + 824604.

Almost surely, 2^666777800 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 666777800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (838422900).

666777800 is an abundant number, since it is smaller than the sum of its proper divisors (1010068000).

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

666777800 is a wasteful number, since it uses less digits than its factorization.

666777800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1155 (or 1146 counting only the distinct ones).

The product of its (nonzero) digits is 592704, while the sum is 47.

The square root of 666777800 is about 25822.0409727814. The cubic root of 666777800 is about 873.6290039937.

The spelling of 666777800 in words is "six hundred sixty-six million, seven hundred seventy-seven thousand, eight hundred".