66721503947520 has 576 divisors, whose sum is σ = 224856597934080. Its totient is φ = 16827806121984.

The previous prime is 66721503947513. The next prime is 66721503947533. The reversal of 66721503947520 is 2574930512766.

66721503947520 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 11368459146 + ... + 11368465014.

It is an arithmetic number, because the mean of its divisors is an integer number (390376038080).

Almost surely, 2^{66721503947520} is an apocalyptic number.

66721503947520 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 66721503947520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (112428298967040).

66721503947520 is an abundant number, since it is smaller than the sum of its proper divisors (158135093986560).

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

66721503947520 is a wasteful number, since it uses less digits than its factorization.

66721503947520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7340 (or 7326 counting only the distinct ones).

The product of its (nonzero) digits is 19051200, while the sum is 57.

The spelling of 66721503947520 in words is "sixty-six trillion, seven hundred twenty-one billion, five hundred three million, nine hundred forty-seven thousand, five hundred twenty".