81735817 has 2 divisors, whose sum is σ = 81735818. Its totient is φ = 81735816.

The previous prime is 81735811. The next prime is 81735877. The reversal of 81735817 is 71853718.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 81288256 + 447561 = 9016^2 + 669^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81735817 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81735817.

It is not a weakly prime, because it can be changed into another prime (81735811) 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, 40867908 + 40867909.

It is an arithmetic number, because the mean of its divisors is an integer number (40867909).

Almost surely, 2^81735817 is an apocalyptic number.

It is an amenable number.

81735817 is a deficient number, since it is larger than the sum of its proper divisors (1).

81735817 is an equidigital number, since it uses as much as digits as its factorization.

81735817 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 47040, while the sum is 40.

The square root of 81735817 is about 9040.7863042990. The cubic root of 81735817 is about 433.9810864077.

The spelling of 81735817 in words is "eighty-one million, seven hundred thirty-five thousand, eight hundred seventeen".