66728994 has 16 divisors (see below), whose sum is σ = 133574880. Its totient is φ = 22223520.

The previous prime is 66728993. The next prime is 66728999. The reversal of 66728994 is 49982766.

It is a happy number.

66728994 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not an unprimeable number, because it can be changed into a prime (66728993) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3717 + ... + 12135.

It is an arithmetic number, because the mean of its divisors is an integer number (8348430).

Almost surely, 2^66728994 is an apocalyptic number.

66728994 is an abundant number, since it is smaller than the sum of its proper divisors (66845886).

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

66728994 is a wasteful number, since it uses less digits than its factorization.

66728994 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9745.

The product of its digits is 1306368, while the sum is 51.

The square root of 66728994 is about 8168.7816717060. The cubic root of 66728994 is about 405.6064561565.

The spelling of 66728994 in words is "sixty-six million, seven hundred twenty-eight thousand, nine hundred ninety-four".