84291209 has 2 divisors, whose sum is σ = 84291210. Its totient is φ = 84291208.

The previous prime is 84291191. The next prime is 84291211. The reversal of 84291209 is 90219248.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 81721600 + 2569609 = 9040^2 + 1603^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-84291209 is a prime.

Together with 84291211, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (84291269) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42145604 + 42145605.

It is an arithmetic number, because the mean of its divisors is an integer number (42145605).

Almost surely, 2^84291209 is an apocalyptic number.

It is an amenable number.

84291209 is a deficient number, since it is larger than the sum of its proper divisors (1).

84291209 is an equidigital number, since it uses as much as digits as its factorization.

84291209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10368, while the sum is 35.

The square root of 84291209 is about 9181.0243981813. The cubic root of 84291209 is about 438.4574236839.

The spelling of 84291209 in words is "eighty-four million, two hundred ninety-one thousand, two hundred nine".