66681012 has 12 divisors (see below), whose sum is σ = 155589056. Its totient is φ = 22227000.

The previous prime is 66681011. The next prime is 66681037. The reversal of 66681012 is 21018666.

It is a tau number, because it is divible by the number of its divisors (12).

It is a super-2 number, since 2×66681012² = 8892714722688288, which contains 22 as substring.

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 polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2778364 + ... + 2778387.

Almost surely, 2^66681012 is an apocalyptic number.

It is an amenable number.

66681012 is an abundant number, since it is smaller than the sum of its proper divisors (88908044).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66681012 is a wasteful number, since it uses less digits than its factorization.

66681012 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5556758 (or 5556756 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 30.

The square root of 66681012 is about 8165.8442306965. The cubic root of 66681012 is about 405.5092146907.

Adding to 66681012 its reverse (21018666), we get a palindrome (87699678).

The spelling of 66681012 in words is "sixty-six million, six hundred eighty-one thousand, twelve".