66681013 has 24 divisors (see below), whose sum is σ = 82946400. Its totient is φ = 53288928.

The previous prime is 66681011. The next prime is 66681037. The reversal of 66681013 is 31018666.

It is not a de Polignac number, because 66681013 - 2¹ = 66681011 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66681011) 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 23 ways as a sum of consecutive naturals, for example, 61843 + ... + 62911.

It is an arithmetic number, because the mean of its divisors is an integer number (3456100).

Almost surely, 2^66681013 is an apocalyptic number.

It is an amenable number.

66681013 is a deficient number, since it is larger than the sum of its proper divisors (16265387).

66681013 is a wasteful number, since it uses less digits than its factorization.

66681013 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1169 (or 1162 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 31.

The square root of 66681013 is about 8165.8442919272. The cubic root of 66681013 is about 405.5092167178.

Adding to 66681013 its reverse (31018666), we get a palindrome (97699679).

The spelling of 66681013 in words is "sixty-six million, six hundred eighty-one thousand, thirteen".