66971435989536 has 384 divisors, whose sum is σ = 216127202054400. Its totient is φ = 20041974374400.

The previous prime is 66971435989501. The next prime is 66971435989541. The reversal of 66971435989536 is 63598953417966.

66971435989536 is a `hidden beast` number, since 6 + 6 + 9 + 7 + 1 + 435 + 98 + 95 + 3 + 6 = 666.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1134099211 + ... + 1134158261.

It is an arithmetic number, because the mean of its divisors is an integer number (562831255350).

Almost surely, 2^{66971435989536} 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 66971435989536, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (108063601027200).

66971435989536 is an abundant number, since it is smaller than the sum of its proper divisors (149155766064864).

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

66971435989536 is a wasteful number, since it uses less digits than its factorization.

66971435989536 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 61849 (or 61835 counting only the distinct ones).

The product of its digits is 7936185600, while the sum is 81.

The spelling of 66971435989536 in words is "sixty-six trillion, nine hundred seventy-one billion, four hundred thirty-five million, nine hundred eighty-nine thousand, five hundred thirty-six".