81698180273 has 2 divisors, whose sum is σ = 81698180274. Its totient is φ = 81698180272.

The previous prime is 81698180269. The next prime is 81698180309. The reversal of 81698180273 is 37208189618.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 56305120369 + 25393059904 = 237287^2 + 159352^2 .

It is a cyclic number.

It is not a de Polignac number, because 81698180273 - 2² = 81698180269 is a prime.

It is not a weakly prime, because it can be changed into another prime (81698180203) 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, 40849090136 + 40849090137.

It is an arithmetic number, because the mean of its divisors is an integer number (40849090137).

Almost surely, 2^81698180273 is an apocalyptic number.

It is an amenable number.

81698180273 is a deficient number, since it is larger than the sum of its proper divisors (1).

81698180273 is an equidigital number, since it uses as much as digits as its factorization.

81698180273 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1161216, while the sum is 53.

The spelling of 81698180273 in words is "eighty-one billion, six hundred ninety-eight million, one hundred eighty thousand, two hundred seventy-three".