27686781 has 12 divisors (see below), whose sum is σ = 42097120. Its totient is φ = 17486280.

The previous prime is 27686777. The next prime is 27686801. The reversal of 27686781 is 18768672.

It is not a de Polignac number, because 27686781 - 2² = 27686777 is a prime.

It is a super-2 number, since 2×27686781² = 1533115684283922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (27686731) 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 11 ways as a sum of consecutive naturals, for example, 80785 + ... + 81126.

Almost surely, 2^27686781 is an apocalyptic number.

It is an amenable number.

27686781 is a deficient number, since it is larger than the sum of its proper divisors (14410339).

27686781 is a wasteful number, since it uses less digits than its factorization.

27686781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 161936 (or 161933 counting only the distinct ones).

The product of its digits is 225792, while the sum is 45.

The square root of 27686781 is about 5261.8229730769. The cubic root of 27686781 is about 302.5223661262.

The spelling of 27686781 in words is "twenty-seven million, six hundred eighty-six thousand, seven hundred eighty-one".