66398320 has 20 divisors (see below), whose sum is σ = 154376280. Its totient is φ = 26559296.

The previous prime is 66398281. The next prime is 66398323. The reversal of 66398320 is 2389366.

It is a happy number.

66398320 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (20).

It is a self number, because there is not a number n which added to its sum of digits gives 66398320.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66398323) 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 3 ways as a sum of consecutive naturals, for example, 414910 + ... + 415069.

It is an arithmetic number, because the mean of its divisors is an integer number (7718814).

Almost surely, 2^66398320 is an apocalyptic number.

It is an amenable number.

66398320 is an abundant number, since it is smaller than the sum of its proper divisors (87977960).

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

66398320 is a wasteful number, since it uses less digits than its factorization.

66398320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 829992 (or 829986 counting only the distinct ones).

The product of its (nonzero) digits is 46656, while the sum is 37.

The square root of 66398320 is about 8148.5164293876. The cubic root of 66398320 is about 404.9353552260.

The spelling of 66398320 in words is "sixty-six million, three hundred ninety-eight thousand, three hundred twenty".