81279728041 has 12 divisors (see below), whose sum is σ = 88926617556. Its totient is φ = 74030856960.

The previous prime is 81279727993. The next prime is 81279728081. The reversal of 81279728041 is 14082797218.

It can be written as a sum of positive squares in 2 ways, for example, as 51774451600 + 29505276441 = 227540^2 + 171771^2 .

It is not a de Polignac number, because 81279728041 - 2²³ = 81271339433 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81279728081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2471260 + ... + 2503933.

It is an arithmetic number, because the mean of its divisors is an integer number (7410551463).

Almost surely, 2^81279728041 is an apocalyptic number.

It is an amenable number.

81279728041 is a deficient number, since it is larger than the sum of its proper divisors (7646889515).

81279728041 is a wasteful number, since it uses less digits than its factorization.

81279728041 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4975272 (or 4975241 counting only the distinct ones).

The product of its (nonzero) digits is 451584, while the sum is 49.

The spelling of 81279728041 in words is "eighty-one billion, two hundred seventy-nine million, seven hundred twenty-eight thousand, forty-one".