66728385837 has 6 divisors (see below), whose sum is σ = 96385446222. Its totient is φ = 44485590552.

The previous prime is 66728385797. The next prime is 66728385859. The reversal of 66728385837 is 73858382766.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 66715790436 + 12595401 = 258294^2 + 3549^2 .

It is not a de Polignac number, because 66728385837 - 2¹⁶ = 66728320301 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66728385337) 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 5 ways as a sum of consecutive naturals, for example, 3707132538 + ... + 3707132555.

It is an arithmetic number, because the mean of its divisors is an integer number (16064241037).

Almost surely, 2^66728385837 is an apocalyptic number.

It is an amenable number.

66728385837 is a deficient number, since it is larger than the sum of its proper divisors (29657060385).

66728385837 is a wasteful number, since it uses less digits than its factorization.

66728385837 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7414265099 (or 7414265096 counting only the distinct ones).

The product of its digits is 81285120, while the sum is 63.

The spelling of 66728385837 in words is "sixty-six billion, seven hundred twenty-eight million, three hundred eighty-five thousand, eight hundred thirty-seven".