11686781 has 2 divisors, whose sum is σ = 11686782. Its totient is φ = 11686780.

The previous prime is 11686777. The next prime is 11686793. The reversal of 11686781 is 18768611.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 8323225 + 3363556 = 2885^2 + 1834^2 .

It is a cyclic number.

It is not a de Polignac number, because 11686781 - 2² = 11686777 is a prime.

It is a super-2 number, since 2×11686781² = 273161700283922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11686711) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5843390 + 5843391.

It is an arithmetic number, because the mean of its divisors is an integer number (5843391).

Almost surely, 2^11686781 is an apocalyptic number.

It is an amenable number.

11686781 is a deficient number, since it is larger than the sum of its proper divisors (1).

11686781 is an equidigital number, since it uses as much as digits as its factorization.

11686781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 16128, while the sum is 38.

The square root of 11686781 is about 3418.5934242024. The cubic root of 11686781 is about 226.9333383408.

The spelling of 11686781 in words is "eleven million, six hundred eighty-six thousand, seven hundred eighty-one".