81159497 has 2 divisors, whose sum is σ = 81159498. Its totient is φ = 81159496.

The previous prime is 81159451. The next prime is 81159509. The reversal of 81159497 is 79495118.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 69572281 + 11587216 = 8341^2 + 3404^2 .

It is a cyclic number.

It is not a de Polignac number, because 81159497 - 2¹² = 81155401 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (81159427) 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, 40579748 + 40579749.

It is an arithmetic number, because the mean of its divisors is an integer number (40579749).

Almost surely, 2^81159497 is an apocalyptic number.

It is an amenable number.

81159497 is a deficient number, since it is larger than the sum of its proper divisors (1).

81159497 is an equidigital number, since it uses as much as digits as its factorization.

81159497 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 90720, while the sum is 44.

The square root of 81159497 is about 9008.8565867151. The cubic root of 81159497 is about 432.9586780772.

The spelling of 81159497 in words is "eighty-one million, one hundred fifty-nine thousand, four hundred ninety-seven".