66205780 has 24 divisors (see below), whose sum is σ = 140710752. Its totient is φ = 26162592.

The previous prime is 66205723. The next prime is 66205781. The reversal of 66205780 is 8750266.

66205780 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66205781) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18282 + ... + 21601.

It is an arithmetic number, because the mean of its divisors is an integer number (5862948).

Almost surely, 2^66205780 is an apocalyptic number.

It is an amenable number.

66205780 is an abundant number, since it is smaller than the sum of its proper divisors (74504972).

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

66205780 is a wasteful number, since it uses less digits than its factorization.

66205780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39975 (or 39973 counting only the distinct ones).

The product of its (nonzero) digits is 20160, while the sum is 34.

The square root of 66205780 is about 8136.6934316097. The cubic root of 66205780 is about 404.5435695283.

The spelling of 66205780 in words is "sixty-six million, two hundred five thousand, seven hundred eighty".