66728385827 has 4 divisors (see below), whose sum is σ = 66732305400. Its totient is φ = 66724466256.

The previous prime is 66728385797. The next prime is 66728385859. The reversal of 66728385827 is 72858382766.

It is a happy number.

66728385827 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 66728385827 - 2²⁸ = 66459950371 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 66728385827.

It is not an unprimeable number, because it can be changed into a prime (66728385527) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1934138 + ... + 1968335.

It is an arithmetic number, because the mean of its divisors is an integer number (16683076350).

Almost surely, 2^66728385827 is an apocalyptic number.

66728385827 is a deficient number, since it is larger than the sum of its proper divisors (3919573).

66728385827 is a wasteful number, since it uses less digits than its factorization.

66728385827 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3919572.

The product of its digits is 54190080, while the sum is 62.

The spelling of 66728385827 in words is "sixty-six billion, seven hundred twenty-eight million, three hundred eighty-five thousand, eight hundred twenty-seven".