66816320 has 56 divisors (see below), whose sum is σ = 161848800. Its totient is φ = 26266112.

The previous prime is 66816317. The next prime is 66816329. The reversal of 66816320 is 2361866.

66816320 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (32).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66816329) 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, 17111 + ... + 20649.

Almost surely, 2^66816320 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 66816320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (80924400).

66816320 is an abundant number, since it is smaller than the sum of its proper divisors (95032480).

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

66816320 is a wasteful number, since it uses less digits than its factorization.

66816320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3615 (or 3605 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 32.

The square root of 66816320 is about 8174.1250296286. The cubic root of 66816320 is about 405.7833135589.

The spelling of 66816320 in words is "sixty-six million, eight hundred sixteen thousand, three hundred twenty".