8020781 has 2 divisors, whose sum is σ = 8020782. Its totient is φ = 8020780.

The previous prime is 8020763. The next prime is 8020783. The reversal of 8020781 is 1870208.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 8008900 + 11881 = 2830^2 + 109^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-8020781 is a prime.

It is a super-2 number, since 2×8020781² = 128665855699922, which contains 22 as substring.

Together with 8020783, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 8020781.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8020783) 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, 4010390 + 4010391.

It is an arithmetic number, because the mean of its divisors is an integer number (4010391).

Almost surely, 2^8020781 is an apocalyptic number.

It is an amenable number.

8020781 is a deficient number, since it is larger than the sum of its proper divisors (1).

8020781 is an equidigital number, since it uses as much as digits as its factorization.

8020781 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 896, while the sum is 26.

The square root of 8020781 is about 2832.0983386881. The cubic root of 8020781 is about 200.1730252681.

Adding to 8020781 its reverse (1870208), we get a palindrome (9890989).

The spelling of 8020781 in words is "eight million, twenty thousand, seven hundred eighty-one".