66081600 has 252 divisors, whose sum is σ = 253653036. Its totient is φ = 16220160.

The previous prime is 66081581. The next prime is 66081611. The reversal of 66081600 is 618066.

It can be written as a sum of positive squares in 6 ways, for example, as 9290304 + 56791296 = 3048^2 + 7536^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 187024 + ... + 187376.

Almost surely, 2^66081600 is an apocalyptic number.

66081600 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 66081600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (126826518).

66081600 is an abundant number, since it is smaller than the sum of its proper divisors (187571436).

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

66081600 is a wasteful number, since it uses less digits than its factorization.

66081600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 394 (or 376 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 66081600 is about 8129.0589861312. The cubic root of 66081600 is about 404.2904815449.

Adding to 66081600 its reverse (618066), we get a palindrome (66699666).

The spelling of 66081600 in words is "sixty-six million, eighty-one thousand, six hundred".