66681113 has 4 divisors (see below), whose sum is σ = 67774308. Its totient is φ = 65587920.

The previous prime is 66681107. The next prime is 66681133. The reversal of 66681113 is 31118666.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 31118666 = 2 ⋅15559333.

It can be written as a sum of positive squares in 2 ways, for example, as 9406489 + 57274624 = 3067^2 + 7568^2 .

It is a cyclic number.

It is not a de Polignac number, because 66681113 - 2¹⁸ = 66418969 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 66681113.

It is not an unprimeable number, because it can be changed into a prime (66681133) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 546506 + ... + 546627.

It is an arithmetic number, because the mean of its divisors is an integer number (16943577).

Almost surely, 2^66681113 is an apocalyptic number.

It is an amenable number.

66681113 is a deficient number, since it is larger than the sum of its proper divisors (1093195).

66681113 is a wasteful number, since it uses less digits than its factorization.

66681113 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1093194.

The product of its digits is 5184, while the sum is 32.

The square root of 66681113 is about 8165.8504149905. The cubic root of 66681113 is about 405.5094194287.

Adding to 66681113 its reverse (31118666), we get a palindrome (97799779).

The spelling of 66681113 in words is "sixty-six million, six hundred eighty-one thousand, one hundred thirteen".