66581200 has 180 divisors, whose sum is σ = 192815040. Its totient is φ = 22014720.

The previous prime is 66581191. The next prime is 66581201. The reversal of 66581200 is 218566.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66581201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 842761 + ... + 842839.

Almost surely, 2^66581200 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 66581200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (96407520).

66581200 is an abundant number, since it is smaller than the sum of its proper divisors (126233840).

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

66581200 is a wasteful number, since it uses less digits than its factorization.

66581200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 154 (or 136 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 28.

The square root of 66581200 is about 8159.7303877028. The cubic root of 66581200 is about 405.3067837623.

Adding to 66581200 its reverse (218566), we get a palindrome (66799766).

The spelling of 66581200 in words is "sixty-six million, five hundred eighty-one thousand, two hundred".