81497081 has 2 divisors, whose sum is σ = 81497082. Its totient is φ = 81497080.

The previous prime is 81497063. The next prime is 81497131. The reversal of 81497081 is 18079418.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 73685056 + 7812025 = 8584^2 + 2795^2 .

It is a cyclic number.

It is not a de Polignac number, because 81497081 - 2²⁶ = 14388217 is a prime.

It is a super-2 number, since 2×81497081² = 13283548423041122, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (81497041) 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, 40748540 + 40748541.

It is an arithmetic number, because the mean of its divisors is an integer number (40748541).

Almost surely, 2^81497081 is an apocalyptic number.

It is an amenable number.

81497081 is a deficient number, since it is larger than the sum of its proper divisors (1).

81497081 is an equidigital number, since it uses as much as digits as its factorization.

81497081 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 16128, while the sum is 38.

The square root of 81497081 is about 9027.5733727287. The cubic root of 81497081 is about 433.5581467916.

The spelling of 81497081 in words is "eighty-one million, four hundred ninety-seven thousand, eighty-one".