66775681 has 12 divisors (see below), whose sum is σ = 77862000. Its totient is φ = 57100680.

The previous prime is 66775679. The next prime is 66775697. The reversal of 66775681 is 18657766.

It is not a de Polignac number, because 66775681 - 2¹ = 66775679 is a prime.

It is a super-2 number, since 2×66775681² = 8917983146027522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66775651) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 23086 + ... + 25816.

It is an arithmetic number, because the mean of its divisors is an integer number (6488500).

Almost surely, 2^66775681 is an apocalyptic number.

It is an amenable number.

66775681 is a deficient number, since it is larger than the sum of its proper divisors (11086319).

66775681 is a wasteful number, since it uses less digits than its factorization.

66775681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3244 (or 3237 counting only the distinct ones).

The product of its digits is 423360, while the sum is 46.

The square root of 66775681 is about 8171.6388197228. The cubic root of 66775681 is about 405.7010284101.

The spelling of 66775681 in words is "sixty-six million, seven hundred seventy-five thousand, six hundred eighty-one".