8011781 has 2 divisors, whose sum is σ = 8011782. Its totient is φ = 8011780.

The previous prime is 8011763. The next prime is 8011789. The reversal of 8011781 is 1871108.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 4622500 + 3389281 = 2150^2 + 1841^2 .

It is a cyclic number.

It is not a de Polignac number, because 8011781 - 2¹⁴ = 7995397 is a prime.

It is a super-2 number, since 2×8011781² = 128377269583922, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 8011781.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8011789) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4005890 + 4005891.

It is an arithmetic number, because the mean of its divisors is an integer number (4005891).

Almost surely, 2^8011781 is an apocalyptic number.

It is an amenable number.

8011781 is a deficient number, since it is larger than the sum of its proper divisors (1).

8011781 is an equidigital number, since it uses as much as digits as its factorization.

8011781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 448, while the sum is 26.

The square root of 8011781 is about 2830.5089648330. The cubic root of 8011781 is about 200.0981268477.

Adding to 8011781 its reverse (1871108), we get a palindrome (9882889).

The spelling of 8011781 in words is "eight million, eleven thousand, seven hundred eighty-one".