866186381 has 2 divisors, whose sum is σ = 866186382. Its totient is φ = 866186380.

The previous prime is 866186353. The next prime is 866186441. The reversal of 866186381 is 183681668.

866186381 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 525968356 + 340218025 = 22934^2 + 18445^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-866186381 is a prime.

It is a super-2 number, since 2×866186381² = 1500557693259754322, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (866186341) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 433093190 + 433093191.

It is an arithmetic number, because the mean of its divisors is an integer number (433093191).

Almost surely, 2^866186381 is an apocalyptic number.

It is an amenable number.

866186381 is a deficient number, since it is larger than the sum of its proper divisors (1).

866186381 is an equidigital number, since it uses as much as digits as its factorization.

866186381 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 331776, while the sum is 47.

The square root of 866186381 is about 29431.0445108562. The cubic root of 866186381 is about 953.2433487885.

The spelling of 866186381 in words is "eight hundred sixty-six million, one hundred eighty-six thousand, three hundred eighty-one".