81497343149 has 2 divisors, whose sum is σ = 81497343150. Its totient is φ = 81497343148.

The previous prime is 81497343127. The next prime is 81497343167. The reversal of 81497343149 is 94134379418.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 68932502500 + 12564840649 = 262550^2 + 112093^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81497343149 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 81497343149.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81497343199) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40748671574 + 40748671575.

It is an arithmetic number, because the mean of its divisors is an integer number (40748671575).

Almost surely, 2^81497343149 is an apocalyptic number.

It is an amenable number.

81497343149 is a deficient number, since it is larger than the sum of its proper divisors (1).

81497343149 is an equidigital number, since it uses as much as digits as its factorization.

81497343149 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2612736, while the sum is 53.

The spelling of 81497343149 in words is "eighty-one billion, four hundred ninety-seven million, three hundred forty-three thousand, one hundred forty-nine".