81333859 has 2 divisors, whose sum is σ = 81333860. Its totient is φ = 81333858.

The previous prime is 81333823. The next prime is 81333869. The reversal of 81333859 is 95833318.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81333859 - 2⁷ = 81333731 is a prime.

It is not a weakly prime, because it can be changed into another prime (81333869) 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, 40666929 + 40666930.

It is an arithmetic number, because the mean of its divisors is an integer number (40666930).

Almost surely, 2^81333859 is an apocalyptic number.

81333859 is a deficient number, since it is larger than the sum of its proper divisors (1).

81333859 is an equidigital number, since it uses as much as digits as its factorization.

81333859 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 77760, while the sum is 40.

The square root of 81333859 is about 9018.5286493973. The cubic root of 81333859 is about 433.2685105534.

The spelling of 81333859 in words is "eighty-one million, three hundred thirty-three thousand, eight hundred fifty-nine".