81517417 has 2 divisors, whose sum is σ = 81517418. Its totient is φ = 81517416.

The previous prime is 81517369. The next prime is 81517433. The reversal of 81517417 is 71471518.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 79637776 + 1879641 = 8924^2 + 1371^2 .

It is a cyclic number.

It is not a de Polignac number, because 81517417 - 2¹⁵ = 81484649 is a prime.

It is equal to p_4752943 and since 81517417 and 4752943 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (81517477) 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, 40758708 + 40758709.

It is an arithmetic number, because the mean of its divisors is an integer number (40758709).

Almost surely, 2^81517417 is an apocalyptic number.

It is an amenable number.

81517417 is a deficient number, since it is larger than the sum of its proper divisors (1).

81517417 is an equidigital number, since it uses as much as digits as its factorization.

81517417 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7840, while the sum is 34.

The square root of 81517417 is about 9028.6996295148. The cubic root of 81517417 is about 433.5942057732.

The spelling of 81517417 in words is "eighty-one million, five hundred seventeen thousand, four hundred seventeen".