81056197 has 2 divisors, whose sum is σ = 81056198. Its totient is φ = 81056196.

The previous prime is 81056191. The next prime is 81056201. The reversal of 81056197 is 79165018.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 56761156 + 24295041 = 7534^2 + 4929^2 .

It is a cyclic number.

It is not a de Polignac number, because 81056197 - 2⁷ = 81056069 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81056191) 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, 40528098 + 40528099.

It is an arithmetic number, because the mean of its divisors is an integer number (40528099).

Almost surely, 2^81056197 is an apocalyptic number.

It is an amenable number.

81056197 is a deficient number, since it is larger than the sum of its proper divisors (1).

81056197 is an equidigital number, since it uses as much as digits as its factorization.

81056197 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15120, while the sum is 37.

The square root of 81056197 is about 9003.1215142305. The cubic root of 81056197 is about 432.7749098112.

The spelling of 81056197 in words is "eighty-one million, fifty-six thousand, one hundred ninety-seven".