66728000720 has 20 divisors (see below), whose sum is σ = 155142601860. Its totient is φ = 26691200256.

The previous prime is 66728000707. The next prime is 66728000761. The reversal of 66728000720 is 2700082766.

66728000720 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 21982213696 + 44745787024 = 148264^2 + 211532^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a Smith number, since the sum of its digits (38) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 417049925 + ... + 417050084.

It is an arithmetic number, because the mean of its divisors is an integer number (7757130093).

Almost surely, 2^66728000720 is an apocalyptic number.

It is an amenable number.

66728000720 is an abundant number, since it is smaller than the sum of its proper divisors (88414601140).

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

66728000720 is a wasteful number, since it uses less digits than its factorization.

66728000720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 834100022 (or 834100016 counting only the distinct ones).

The product of its (nonzero) digits is 56448, while the sum is 38.

The spelling of 66728000720 in words is "sixty-six billion, seven hundred twenty-eight million, seven hundred twenty", and thus it is an aban number.