84731809 has 2 divisors, whose sum is σ = 84731810. Its totient is φ = 84731808.

The previous prime is 84731783. The next prime is 84731819. The reversal of 84731809 is 90813748.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 84640000 + 91809 = 9200^2 + 303^2 .

It is a cyclic number.

It is not a de Polignac number, because 84731809 - 2¹⁹ = 84207521 is a prime.

It is not a weakly prime, because it can be changed into another prime (84731819) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42365904 + 42365905.

It is an arithmetic number, because the mean of its divisors is an integer number (42365905).

Almost surely, 2^84731809 is an apocalyptic number.

It is an amenable number.

84731809 is a deficient number, since it is larger than the sum of its proper divisors (1).

84731809 is an equidigital number, since it uses as much as digits as its factorization.

84731809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 48384, while the sum is 40.

The square root of 84731809 is about 9204.9882672386. The cubic root of 84731809 is about 439.2200525044.

The spelling of 84731809 in words is "eighty-four million, seven hundred thirty-one thousand, eight hundred nine".