66991456584000 has 1344 divisors, whose sum is σ = 272236692000000. Its totient is φ = 15588926668800.

The previous prime is 66991456583977. The next prime is 66991456584001. The reversal of 66991456584000 is 48565419966.

66991456584000 is a `hidden beast` number, since 6 + 6 + 9 + 9 + 1 + 45 + 6 + 584 + 0 + 0 + 0 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66991456584001) by changing a digit.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 8874212226 + ... + 8874219774.

It is an arithmetic number, because the mean of its divisors is an integer number (202557062500).

Almost surely, 2^{66991456584000} is an apocalyptic number.

66991456584000 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 66991456584000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (136118346000000).

66991456584000 is an abundant number, since it is smaller than the sum of its proper divisors (205245235416000).

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

66991456584000 is a wasteful number, since it uses less digits than its factorization.

66991456584000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8113 (or 8090 counting only the distinct ones).

The product of its (nonzero) digits is 55987200, while the sum is 63.

The spelling of 66991456584000 in words is "sixty-six trillion, nine hundred ninety-one billion, four hundred fifty-six million, five hundred eighty-four thousand".