66558237278720 has 320 divisors, whose sum is σ = 186023324995200. Its totient is φ = 22570287759360.

The previous prime is 66558237278707. The next prime is 66558237278779. The reversal of 66558237278720 is 2787273285566.

It is a tau number, because it is divible by the number of its divisors (320).

It is a Harshad number since it is a multiple of its sum of digits (68).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 51542711 + ... + 52818249.

It is an arithmetic number, because the mean of its divisors is an integer number (581322890610).

Almost surely, 2^{66558237278720} 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 66558237278720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (93011662497600).

66558237278720 is an abundant number, since it is smaller than the sum of its proper divisors (119465087716480).

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

66558237278720 is a wasteful number, since it uses less digits than its factorization.

66558237278720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1275699 (or 1275683 counting only the distinct ones).

The product of its (nonzero) digits is 474163200, while the sum is 68.

The spelling of 66558237278720 in words is "sixty-six trillion, five hundred fifty-eight billion, two hundred thirty-seven million, two hundred seventy-eight thousand, seven hundred twenty".