66644320 has 96 divisors (see below), whose sum is σ = 166561920. Its totient is φ = 25159680.

The previous prime is 66644309. The next prime is 66644323. The reversal of 66644320 is 2344666.

It is a nialpdrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66644323) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 245785 + ... + 246055.

It is an arithmetic number, because the mean of its divisors is an integer number (1735020).

Almost surely, 2^66644320 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 66644320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (83280960).

66644320 is an abundant number, since it is smaller than the sum of its proper divisors (99917600).

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

66644320 is a wasteful number, since it uses less digits than its factorization.

66644320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 368 (or 360 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 31.

The square root of 66644320 is about 8163.5972463124. The cubic root of 66644320 is about 405.4348223283.

Adding to 66644320 its reverse (2344666), we get a palindrome (68988986).

The spelling of 66644320 in words is "sixty-six million, six hundred forty-four thousand, three hundred twenty".