81389263 has 2 divisors, whose sum is σ = 81389264. Its totient is φ = 81389262.

The previous prime is 81389237. The next prime is 81389279. The reversal of 81389263 is 36298318.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81389263 - 2⁹ = 81388751 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81389213) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40694631 + 40694632.

It is an arithmetic number, because the mean of its divisors is an integer number (40694632).

Almost surely, 2^81389263 is an apocalyptic number.

81389263 is a deficient number, since it is larger than the sum of its proper divisors (1).

81389263 is an equidigital number, since it uses as much as digits as its factorization.

81389263 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 62208, while the sum is 40.

The square root of 81389263 is about 9021.5998026958. The cubic root of 81389263 is about 433.3668679505.

The spelling of 81389263 in words is "eighty-one million, three hundred eighty-nine thousand, two hundred sixty-three".