81126575609 has 2 divisors, whose sum is σ = 81126575610. Its totient is φ = 81126575608.

The previous prime is 81126575599. The next prime is 81126575623. The reversal of 81126575609 is 90657562118.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 74024805625 + 7101769984 = 272075^2 + 84272^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81126575609 is a prime.

It is not a weakly prime, because it can be changed into another prime (81126575669) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40563287804 + 40563287805.

It is an arithmetic number, because the mean of its divisors is an integer number (40563287805).

Almost surely, 2^81126575609 is an apocalyptic number.

It is an amenable number.

81126575609 is a deficient number, since it is larger than the sum of its proper divisors (1).

81126575609 is an equidigital number, since it uses as much as digits as its factorization.

81126575609 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 907200, while the sum is 50.

The spelling of 81126575609 in words is "eighty-one billion, one hundred twenty-six million, five hundred seventy-five thousand, six hundred nine".