66728563469 has 4 divisors (see below), whose sum is σ = 66907460796. Its totient is φ = 66549666144.

The previous prime is 66728563441. The next prime is 66728563471. The reversal of 66728563469 is 96436582766.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 55946440900 + 10782122569 = 236530^2 + 103837^2 .

It is a cyclic number.

It is not a de Polignac number, because 66728563469 - 2²⁸ = 66460128013 is a prime.

It is a super-2 number, since 2×66728563469² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66728563409) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 89448104 + ... + 89448849.

It is an arithmetic number, because the mean of its divisors is an integer number (16726865199).

Almost surely, 2^66728563469 is an apocalyptic number.

It is an amenable number.

66728563469 is a deficient number, since it is larger than the sum of its proper divisors (178897327).

66728563469 is a wasteful number, since it uses less digits than its factorization.

66728563469 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 178897326.

The product of its digits is 78382080, while the sum is 62.

The spelling of 66728563469 in words is "sixty-six billion, seven hundred twenty-eight million, five hundred sixty-three thousand, four hundred sixty-nine".