66728385591 has 16 divisors (see below), whose sum is σ = 101695106304. Its totient is φ = 38125347264.

The previous prime is 66728385587. The next prime is 66728385613. The reversal of 66728385591 is 19558382766.

It is not a de Polignac number, because 66728385591 - 2² = 66728385587 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66728389591) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 53206 + ... + 369171.

It is an arithmetic number, because the mean of its divisors is an integer number (6355944144).

Almost surely, 2^66728385591 is an apocalyptic number.

66728385591 is a deficient number, since it is larger than the sum of its proper divisors (34966720713).

66728385591 is a wasteful number, since it uses less digits than its factorization.

66728385591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 429910.

The product of its digits is 21772800, while the sum is 60.

The spelling of 66728385591 in words is "sixty-six billion, seven hundred twenty-eight million, three hundred eighty-five thousand, five hundred ninety-one".