81392127617 has 2 divisors, whose sum is σ = 81392127618. Its totient is φ = 81392127616.

The previous prime is 81392127601. The next prime is 81392127631. The reversal of 81392127617 is 71672129318.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 79048696336 + 2343431281 = 281156^2 + 48409^2 .

It is a cyclic number.

It is not a de Polignac number, because 81392127617 - 2⁴ = 81392127601 is a prime.

It is not a weakly prime, because it can be changed into another prime (81392127017) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40696063808 + 40696063809.

It is an arithmetic number, because the mean of its divisors is an integer number (40696063809).

Almost surely, 2^81392127617 is an apocalyptic number.

It is an amenable number.

81392127617 is a deficient number, since it is larger than the sum of its proper divisors (1).

81392127617 is an equidigital number, since it uses as much as digits as its factorization.

81392127617 is an evil number, because the sum of its binary digits is even.

The product of its digits is 254016, while the sum is 47.

The spelling of 81392127617 in words is "eighty-one billion, three hundred ninety-two million, one hundred twenty-seven thousand, six hundred seventeen".