81708841 has 2 divisors, whose sum is σ = 81708842. Its totient is φ = 81708840.

The previous prime is 81708779. The next prime is 81708871. The reversal of 81708841 is 14880718.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 77792400 + 3916441 = 8820^2 + 1979^2 .

It is a cyclic number.

It is not a de Polignac number, because 81708841 - 2⁷ = 81708713 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81708841.

It is not a weakly prime, because it can be changed into another prime (81708871) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40854420 + 40854421.

It is an arithmetic number, because the mean of its divisors is an integer number (40854421).

Almost surely, 2^81708841 is an apocalyptic number.

It is an amenable number.

81708841 is a deficient number, since it is larger than the sum of its proper divisors (1).

81708841 is an equidigital number, since it uses as much as digits as its factorization.

81708841 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 14336, while the sum is 37.

The square root of 81708841 is about 9039.2942755505. The cubic root of 81708841 is about 433.9333376060.

The spelling of 81708841 in words is "eighty-one million, seven hundred eight thousand, eight hundred forty-one".