66400312320 has 528 divisors, whose sum is σ = 244288980000. Its totient is φ = 16629497856.

The previous prime is 66400312271. The next prime is 66400312337. The reversal of 66400312320 is 2321300466.

66400312320 is a `hidden beast` number, since 6 + 640 + 0 + 3 + 12 + 3 + 2 + 0 = 666.

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, 130452226 + ... + 130452734.

Almost surely, 2^66400312320 is an apocalyptic number.

66400312320 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 66400312320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (122144490000).

66400312320 is an abundant number, since it is smaller than the sum of its proper divisors (177888667680).

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

66400312320 is a wasteful number, since it uses less digits than its factorization.

66400312320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 708 (or 687 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 27.

Adding to 66400312320 its reverse (2321300466), we get a palindrome (68721612786).

The spelling of 66400312320 in words is "sixty-six billion, four hundred million, three hundred twelve thousand, three hundred twenty".