66428320 has 144 divisors (see below), whose sum is σ = 188312040. Its totient is φ = 22063104.

The previous prime is 66428291. The next prime is 66428339. The reversal of 66428320 is 2382466.

66428320 = T₄₉ + T₅₀ + ... + T₇₃₅.

It can be written as a sum of positive squares in 4 ways, for example, as 66389904 + 38416 = 8148^2 + 196^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 289966 + ... + 290194.

Almost surely, 2^66428320 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 66428320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (94156020).

66428320 is an abundant number, since it is smaller than the sum of its proper divisors (121883720).

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

66428320 is a wasteful number, since it uses less digits than its factorization.

66428320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 295 (or 280 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 31.

The square root of 66428320 is about 8150.3570473937. The cubic root of 66428320 is about 404.9963318268.

The spelling of 66428320 in words is "sixty-six million, four hundred twenty-eight thousand, three hundred twenty".