81091465896401 has 2 divisors, whose sum is σ = 81091465896402. Its totient is φ = 81091465896400.

The previous prime is 81091465896361. The next prime is 81091465896407. The reversal of 81091465896401 is 10469856419018.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 72989700646801 + 8101765249600 = 8543401^2 + 2846360^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81091465896401 is a prime.

It is not a weakly prime, because it can be changed into another prime (81091465896407) 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, 40545732948200 + 40545732948201.

It is an arithmetic number, because the mean of its divisors is an integer number (40545732948201).

Almost surely, 2^{81091465896401} is an apocalyptic number.

It is an amenable number.

81091465896401 is a deficient number, since it is larger than the sum of its proper divisors (1).

81091465896401 is an equidigital number, since it uses as much as digits as its factorization.

81091465896401 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 14929920, while the sum is 62.

The spelling of 81091465896401 in words is "eighty-one trillion, ninety-one billion, four hundred sixty-five million, eight hundred ninety-six thousand, four hundred one".