66544333220 has 96 divisors (see below), whose sum is σ = 145978519680.
Its totient is φ = 25449016320.
The previous prime is 66544333181. The next prime is 66544333223. The reversal of 66544333220 is 2233344566.
Adding to 66544333220 its reverse (2233344566), we get a palindrome (68777677786).
It is a nialpdrome in base 10.
It is not an unprimeable number, because it can be changed into a prime (66544333223) by changing a digit.
It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 43463855 + ... + 43465385.
It is an arithmetic number, because the mean of its divisors is an integer number (1520609580).
Almost surely, 266544333220 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 66544333220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (72989259840).
66544333220 is an abundant number, since it is smaller than the sum of its proper divisors (79434186460).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
66544333220 is a wasteful number, since it uses less digits than its factorization.
With its predecessor (66544333219) it forms a Ruth-Aaron pair, since the sum of their distinct prime factors is the same (2251).
66544333220 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 2253 (or 2251 counting only the distinct ones).
The product of its (nonzero) digits is 311040, while the sum is 38.
The spelling of 66544333220 in words is "sixty-six billion, five hundred forty-four million, three hundred thirty-three thousand, two hundred twenty".