66686926321 has 4 divisors (see below), whose sum is σ = 66726317812. Its totient is φ = 66647534832.

The previous prime is 66686926303. The next prime is 66686926367. The reversal of 66686926321 is 12362968666.

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 12602307600 + 54084618721 = 112260^2 + 232561^2 .

It is a cyclic number.

It is not a de Polignac number, because 66686926321 - 2⁵ = 66686926289 is a prime.

It is a super-2 number, since 2×66686926321² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66686926381) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19693206 + ... + 19696591.

It is an arithmetic number, because the mean of its divisors is an integer number (16681579453).

Almost surely, 2^66686926321 is an apocalyptic number.

It is an amenable number.

66686926321 is a deficient number, since it is larger than the sum of its proper divisors (39391491).

66686926321 is a wasteful number, since it uses less digits than its factorization.

66686926321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39391490.

The product of its digits is 6718464, while the sum is 55.

The spelling of 66686926321 in words is "sixty-six billion, six hundred eighty-six million, nine hundred twenty-six thousand, three hundred twenty-one".