81728146091 has 2 divisors, whose sum is σ = 81728146092. Its totient is φ = 81728146090.

The previous prime is 81728146063. The next prime is 81728146099. The reversal of 81728146091 is 19064182718.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81728146091 - 2¹⁰ = 81728145067 is a prime.

It is not a weakly prime, because it can be changed into another prime (81728146099) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40864073045 + 40864073046.

It is an arithmetic number, because the mean of its divisors is an integer number (40864073046).

Almost surely, 2^81728146091 is an apocalyptic number.

81728146091 is a deficient number, since it is larger than the sum of its proper divisors (1).

81728146091 is an equidigital number, since it uses as much as digits as its factorization.

81728146091 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 193536, while the sum is 47.

The spelling of 81728146091 in words is "eighty-one billion, seven hundred twenty-eight million, one hundred forty-six thousand, ninety-one".