81928219073 has 2 divisors, whose sum is σ = 81928219074. Its totient is φ = 81928219072.

The previous prime is 81928219019. The next prime is 81928219111. The reversal of 81928219073 is 37091282918.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 74860790449 + 7067428624 = 273607^2 + 84068^2 .

It is a cyclic number.

It is not a de Polignac number, because 81928219073 - 2¹⁰ = 81928218049 is a prime.

It is not a weakly prime, because it can be changed into another prime (81928219003) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40964109536 + 40964109537.

It is an arithmetic number, because the mean of its divisors is an integer number (40964109537).

Almost surely, 2^81928219073 is an apocalyptic number.

It is an amenable number.

81928219073 is a deficient number, since it is larger than the sum of its proper divisors (1).

81928219073 is an equidigital number, since it uses as much as digits as its factorization.

81928219073 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 435456, while the sum is 50.

The spelling of 81928219073 in words is "eighty-one billion, nine hundred twenty-eight million, two hundred nineteen thousand, seventy-three".