80981993 has 2 divisors, whose sum is σ = 80981994. Its totient is φ = 80981992.

The previous prime is 80981981. The next prime is 80982019. The reversal of 80981993 is 39918908.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 51093904 + 29888089 = 7148^2 + 5467^2 .

It is a cyclic number.

It is not a de Polignac number, because 80981993 - 2⁸ = 80981737 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (80981963) 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, 40490996 + 40490997.

It is an arithmetic number, because the mean of its divisors is an integer number (40490997).

Almost surely, 2^80981993 is an apocalyptic number.

It is an amenable number.

80981993 is a deficient number, since it is larger than the sum of its proper divisors (1).

80981993 is an equidigital number, since it uses as much as digits as its factorization.

80981993 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 139968, while the sum is 47.

The square root of 80981993 is about 8998.9995555062. Note that the first 3 decimals coincide. The cubic root of 80981993 is about 432.6428062617.

The spelling of 80981993 in words is "eighty million, nine hundred eighty-one thousand, nine hundred ninety-three".