81705133 has 2 divisors, whose sum is σ = 81705134. Its totient is φ = 81705132.

The previous prime is 81705121. The next prime is 81705157. The reversal of 81705133 is 33150718.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 59028489 + 22676644 = 7683^2 + 4762^2 .

It is a cyclic number.

It is not a de Polignac number, because 81705133 - 2¹⁷ = 81574061 is a prime.

It is equal to p_4763242 and since 81705133 and 4763242 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81706133) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40852566 + 40852567.

It is an arithmetic number, because the mean of its divisors is an integer number (40852567).

Almost surely, 2^81705133 is an apocalyptic number.

It is an amenable number.

81705133 is a deficient number, since it is larger than the sum of its proper divisors (1).

81705133 is an equidigital number, since it uses as much as digits as its factorization.

81705133 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2520, while the sum is 28.

The square root of 81705133 is about 9039.0891687161. The cubic root of 81705133 is about 433.9267734483.

The spelling of 81705133 in words is "eighty-one million, seven hundred five thousand, one hundred thirty-three".