66688733344489 has 3 divisors (see below), whose sum is σ = 66688741510807. Its totient is φ = 66688725178172.

The previous prime is 66688733344483. The next prime is 66688733344501. The reversal of 66688733344489 is 98444333788666.

The square root of 66688733344489 is 8166317.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 57470878712025 + 9217854632464 = 7580955^2 + 3036092^2 .

It is not a de Polignac number, because 66688733344489 - 2¹⁵ = 66688733311721 is a prime.

It is a super-2 number, since 2×66688733344489² (a number of 28 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66688733344483) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 4083159 + ... + 12249475.

Almost surely, 2^{66688733344489} is an apocalyptic number.

66688733344489 is the 8166317-th square number.

66688733344489 is the 4083159-th centered octagonal number.

It is an amenable number.

66688733344489 is a deficient number, since it is larger than the sum of its proper divisors (8166318).

66688733344489 is an frugal number, since it uses more digits than its factorization.

66688733344489 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16332634 (or 8166317 counting only the distinct ones).

The product of its digits is 12039487488, while the sum is 79.

The spelling of 66688733344489 in words is "sixty-six trillion, six hundred eighty-eight billion, seven hundred thirty-three million, three hundred forty-four thousand, four hundred eighty-nine".