66999745800 has 432 divisors, whose sum is σ = 244880604540. Its totient is φ = 16408903680.

The previous prime is 66999745793. The next prime is 66999745811. The reversal of 66999745800 is 854799966.

It is a happy number.

66999745800 is a `hidden beast` number, since 6 + 6 + 99 + 97 + 458 + 0 + 0 = 666.

It can be written as a sum of positive squares in 18 ways, for example, as 190937124 + 66808808676 = 13818^2 + 258474^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 107 ways as a sum of consecutive naturals, for example, 78178972 + ... + 78179828.

Almost surely, 2^66999745800 is an apocalyptic number.

66999745800 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 66999745800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (122440302270).

66999745800 is an abundant number, since it is smaller than the sum of its proper divisors (177880858740).

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

66999745800 is a wasteful number, since it uses less digits than its factorization.

66999745800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1162 (or 1137 counting only the distinct ones).

The product of its (nonzero) digits is 29393280, while the sum is 63.

The spelling of 66999745800 in words is "sixty-six billion, nine hundred ninety-nine million, seven hundred forty-five thousand, eight hundred".