66475872681 has 4 divisors (see below), whose sum is σ = 88634496912. Its totient is φ = 44317248452.

The previous prime is 66475872653. The next prime is 66475872739. The reversal of 66475872681 is 18627857466.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 66475872681 - 2¹⁴ = 66475856297 is a prime.

It is a super-2 number, since 2×66475872681² (a number of 22 digits) contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (66475876681) 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 3 ways as a sum of consecutive naturals, for example, 11079312111 + ... + 11079312116.

It is an arithmetic number, because the mean of its divisors is an integer number (22158624228).

Almost surely, 2^66475872681 is an apocalyptic number.

It is an amenable number.

66475872681 is a deficient number, since it is larger than the sum of its proper divisors (22158624231).

66475872681 is a wasteful number, since it uses less digits than its factorization.

66475872681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22158624230.

The product of its digits is 27095040, while the sum is 60.

The spelling of 66475872681 in words is "sixty-six billion, four hundred seventy-five million, eight hundred seventy-two thousand, six hundred eighty-one".