66646103993568 has 960 divisors, whose sum is σ = 230100896551680. Its totient is φ = 18708234854400.

The previous prime is 66646103993561. The next prime is 66646103993593. The reversal of 66646103993568 is 86539930164666.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a junction number, because it is equal to n+sod(n) for n = 66646103993496 and 66646103993505.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66646103993561) by changing a digit.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 8814452508 + ... + 8814460068.

It is an arithmetic number, because the mean of its divisors is an integer number (239688433908).

Almost surely, 2^{66646103993568} 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 66646103993568, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (115050448275840).

66646103993568 is an abundant number, since it is smaller than the sum of its proper divisors (163454792558112).

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

66646103993568 is a wasteful number, since it uses less digits than its factorization.

66646103993568 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7973 (or 7956 counting only the distinct ones).

The product of its (nonzero) digits is 906992640, while the sum is 72.

The spelling of 66646103993568 in words is "sixty-six trillion, six hundred forty-six billion, one hundred three million, nine hundred ninety-three thousand, five hundred sixty-eight".