8442781 has 2 divisors, whose sum is σ = 8442782. Its totient is φ = 8442780.

The previous prime is 8442779. The next prime is 8442793. The reversal of 8442781 is 1872448.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 4305625 + 4137156 = 2075^2 + 2034^2 .

It is a cyclic number.

It is not a de Polignac number, because 8442781 - 2¹ = 8442779 is a prime.

It is a super-2 number, since 2×8442781² = 142561102027922, which contains 22 as substring.

Together with 8442779, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8442481) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4221390 + 4221391.

It is an arithmetic number, because the mean of its divisors is an integer number (4221391).

Almost surely, 2^8442781 is an apocalyptic number.

It is an amenable number.

8442781 is a deficient number, since it is larger than the sum of its proper divisors (1).

8442781 is an equidigital number, since it uses as much as digits as its factorization.

8442781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 14336, while the sum is 34.

The square root of 8442781 is about 2905.6463996846. The cubic root of 8442781 is about 203.6237859847.

The spelling of 8442781 in words is "eight million, four hundred forty-two thousand, seven hundred eighty-one".