81996617 has 2 divisors, whose sum is σ = 81996618. Its totient is φ = 81996616.

The previous prime is 81996611. The next prime is 81996619. The reversal of 81996617 is 71669918.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 74926336 + 7070281 = 8656^2 + 2659^2 .

It is a cyclic number.

It is not a de Polignac number, because 81996617 - 2⁸ = 81996361 is a prime.

Together with 81996619, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (81996611) 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, 40998308 + 40998309.

It is an arithmetic number, because the mean of its divisors is an integer number (40998309).

Almost surely, 2^81996617 is an apocalyptic number.

It is an amenable number.

81996617 is a deficient number, since it is larger than the sum of its proper divisors (1).

81996617 is an equidigital number, since it uses as much as digits as its factorization.

81996617 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 163296, while the sum is 47.

The square root of 81996617 is about 9055.1983412844. The cubic root of 81996617 is about 434.4421739496.

The spelling of 81996617 in words is "eighty-one million, nine hundred ninety-six thousand, six hundred seventeen".