8445781 has 2 divisors, whose sum is σ = 8445782. Its totient is φ = 8445780.

The previous prime is 8445769. The next prime is 8445797. The reversal of 8445781 is 1875448.

8445781 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., 7789681 + 656100 = 2791^2 + 810^2 .

It is a cyclic number.

It is not a de Polignac number, because 8445781 - 2¹⁹ = 7921493 is a prime.

It is a super-2 number, since 2×8445781² = 142662433399922, which contains 22 as substring.

It is an Ulam number.

It is a self number, because there is not a number n which added to its sum of digits gives 8445781.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8445751) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4222890 + 4222891.

It is an arithmetic number, because the mean of its divisors is an integer number (4222891).

Almost surely, 2^8445781 is an apocalyptic number.

It is an amenable number.

8445781 is a deficient number, since it is larger than the sum of its proper divisors (1).

8445781 is an equidigital number, since it uses as much as digits as its factorization.

8445781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 35840, while the sum is 37.

The square root of 8445781 is about 2906.1625900834. The cubic root of 8445781 is about 203.6479012226.

The spelling of 8445781 in words is "eight million, four hundred forty-five thousand, seven hundred eighty-one".