84218009 has 2 divisors, whose sum is σ = 84218010. Its totient is φ = 84218008.

The previous prime is 84217997. The next prime is 84218021. The reversal of 84218009 is 90081248.

It is a happy number.

It is a balanced prime because it is at equal distance from previous prime (84217997) and next prime (84218021).

It can be written as a sum of positive squares in only one way, i.e., 43296400 + 40921609 = 6580^2 + 6397^2 .

It is a cyclic number.

It is not a de Polignac number, because 84218009 - 2⁴ = 84217993 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (84218039) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42109004 + 42109005.

It is an arithmetic number, because the mean of its divisors is an integer number (42109005).

Almost surely, 2^84218009 is an apocalyptic number.

It is an amenable number.

84218009 is a deficient number, since it is larger than the sum of its proper divisors (1).

84218009 is an equidigital number, since it uses as much as digits as its factorization.

84218009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4608, while the sum is 32.

The square root of 84218009 is about 9177.0370490698. The cubic root of 84218009 is about 438.3304654916.

The spelling of 84218009 in words is "eighty-four million, two hundred eighteen thousand, nine".