66512620800 has 864 divisors, whose sum is σ = 255422818560. Its totient is φ = 16920576000.

The previous prime is 66512620747. The next prime is 66512620829. The reversal of 66512620800 is 802621566.

66512620800 is a `hidden beast` number, since 6 + 6 + 512 + 62 + 0 + 80 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (864).

It is a super-3 number, since 3×66512620800³ (a number of 33 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

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 95 ways as a sum of consecutive naturals, for example, 645753549 + ... + 645753651.

Almost surely, 2^66512620800 is an apocalyptic number.

66512620800 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 66512620800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (127711409280).

66512620800 is an abundant number, since it is smaller than the sum of its proper divisors (188910197760).

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

66512620800 is a wasteful number, since it uses less digits than its factorization.

66512620800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 276 (or 251 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 36.

The spelling of 66512620800 in words is "sixty-six billion, five hundred twelve million, six hundred twenty thousand, eight hundred".