81759943 has 2 divisors, whose sum is σ = 81759944. Its totient is φ = 81759942.

The previous prime is 81759941. The next prime is 81759971. The reversal of 81759943 is 34995718.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81759943 - 2¹ = 81759941 is a prime.

Together with 81759941, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 81759893 and 81759902.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81759941) 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, 40879971 + 40879972.

It is an arithmetic number, because the mean of its divisors is an integer number (40879972).

Almost surely, 2^81759943 is an apocalyptic number.

81759943 is a deficient number, since it is larger than the sum of its proper divisors (1).

81759943 is an equidigital number, since it uses as much as digits as its factorization.

81759943 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 272160, while the sum is 46.

The square root of 81759943 is about 9042.1204924509. The cubic root of 81759943 is about 434.0237816752.

The spelling of 81759943 in words is "eighty-one million, seven hundred fifty-nine thousand, nine hundred forty-three".