81728146099 has 2 divisors, whose sum is σ = 81728146100. Its totient is φ = 81728146098.

The previous prime is 81728146091. The next prime is 81728146117. The reversal of 81728146099 is 99064182718.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81728146099 - 2³ = 81728146091 is a prime.

It is not a weakly prime, because it can be changed into another prime (81728146091) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40864073049 + 40864073050.

It is an arithmetic number, because the mean of its divisors is an integer number (40864073050).

Almost surely, 2^81728146099 is an apocalyptic number.

81728146099 is a deficient number, since it is larger than the sum of its proper divisors (1).

81728146099 is an equidigital number, since it uses as much as digits as its factorization.

81728146099 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1741824, while the sum is 55.

The spelling of 81728146099 in words is "eighty-one billion, seven hundred twenty-eight million, one hundred forty-six thousand, ninety-nine".