8427781 has 2 divisors, whose sum is σ = 8427782. Its totient is φ = 8427780.

The previous prime is 8427779. The next prime is 8427787. The reversal of 8427781 is 1877248.

8427781 is digitally balanced in base 3, 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., 7344100 + 1083681 = 2710^2 + 1041^2 .

It is a cyclic number.

It is not a de Polignac number, because 8427781 - 2¹ = 8427779 is a prime.

It is a super-2 number, since 2×8427781² = 142054985167922, which contains 22 as substring.

Together with 8427779, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 8427781.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8427787) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4213890 + 4213891.

It is an arithmetic number, because the mean of its divisors is an integer number (4213891).

Almost surely, 2^8427781 is an apocalyptic number.

It is an amenable number.

8427781 is a deficient number, since it is larger than the sum of its proper divisors (1).

8427781 is an equidigital number, since it uses as much as digits as its factorization.

8427781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 25088, while the sum is 37.

The square root of 8427781 is about 2903.0640709430. The cubic root of 8427781 is about 203.5031240276.

The spelling of 8427781 in words is "eight million, four hundred twenty-seven thousand, seven hundred eighty-one".