81360889 has 2 divisors, whose sum is σ = 81360890. Its totient is φ = 81360888.

The previous prime is 81360841. The next prime is 81360893. The reversal of 81360889 is 98806318.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 77088400 + 4272489 = 8780^2 + 2067^2 .

It is a cyclic number.

It is not a de Polignac number, because 81360889 - 2¹³ = 81352697 is a prime.

It is not a weakly prime, because it can be changed into another prime (81360809) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40680444 + 40680445.

It is an arithmetic number, because the mean of its divisors is an integer number (40680445).

Almost surely, 2^81360889 is an apocalyptic number.

It is an amenable number.

81360889 is a deficient number, since it is larger than the sum of its proper divisors (1).

81360889 is an equidigital number, since it uses as much as digits as its factorization.

81360889 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 82944, while the sum is 43.

The square root of 81360889 is about 9020.0271063894. The cubic root of 81360889 is about 433.3165018446.

The spelling of 81360889 in words is "eighty-one million, three hundred sixty thousand, eight hundred eighty-nine".