66289616640 has 432 divisors, whose sum is σ = 250020624672. Its totient is φ = 16117825536.

The previous prime is 66289616579. The next prime is 66289616651. The reversal of 66289616640 is 4661698266.

66289616640 is a `hidden beast` number, since 6 + 628 + 9 + 6 + 1 + 6 + 6 + 4 + 0 = 666.

66289616640 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 12427414 + ... + 12432746.

It is an arithmetic number, because the mean of its divisors is an integer number (578751446).

Almost surely, 2^66289616640 is an apocalyptic number.

66289616640 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66289616640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (125010312336).

66289616640 is an abundant number, since it is smaller than the sum of its proper divisors (183731008032).

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

66289616640 is a wasteful number, since it uses less digits than its factorization.

66289616640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5456 (or 5439 counting only the distinct ones).

The product of its (nonzero) digits is 4478976, while the sum is 54.

The spelling of 66289616640 in words is "sixty-six billion, two hundred eighty-nine million, six hundred sixteen thousand, six hundred forty".