81293138057009 has 2 divisors, whose sum is σ = 81293138057010. Its totient is φ = 81293138057008.

The previous prime is 81293138056993. The next prime is 81293138057017. The reversal of 81293138057009 is 90075083139218.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 47986931107600 + 33306206949409 = 6927260^2 + 5771153^2 .

It is a cyclic number.

It is not a de Polignac number, because 81293138057009 - 2⁴ = 81293138056993 is a prime.

It is not a weakly prime, because it can be changed into another prime (81293138057029) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40646569028504 + 40646569028505.

It is an arithmetic number, because the mean of its divisors is an integer number (40646569028505).

Almost surely, 2^{81293138057009} is an apocalyptic number.

It is an amenable number.

81293138057009 is a deficient number, since it is larger than the sum of its proper divisors (1).

81293138057009 is an equidigital number, since it uses as much as digits as its factorization.

81293138057009 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3265920, while the sum is 56.

The spelling of 81293138057009 in words is "eighty-one trillion, two hundred ninety-three billion, one hundred thirty-eight million, fifty-seven thousand, nine".