43420781 has 2 divisors, whose sum is σ = 43420782. Its totient is φ = 43420780.

The previous prime is 43420777. The next prime is 43420799. The reversal of 43420781 is 18702434.

43420781 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., 37319881 + 6100900 = 6109^2 + 2470^2 .

It is a cyclic number.

It is not a de Polignac number, because 43420781 - 2² = 43420777 is a prime.

It is a super-2 number, since 2×43420781² = 3770728445299922, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (43420381) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21710390 + 21710391.

It is an arithmetic number, because the mean of its divisors is an integer number (21710391).

Almost surely, 2^43420781 is an apocalyptic number.

It is an amenable number.

43420781 is a deficient number, since it is larger than the sum of its proper divisors (1).

43420781 is an equidigital number, since it uses as much as digits as its factorization.

43420781 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5376, while the sum is 29.

The square root of 43420781 is about 6589.4446655238. Note that the first 3 decimals coincide. The cubic root of 43420781 is about 351.4788609105.

The spelling of 43420781 in words is "forty-three million, four hundred twenty thousand, seven hundred eighty-one".