84435809 has 2 divisors, whose sum is σ = 84435810. Its totient is φ = 84435808.

The previous prime is 84435779. The next prime is 84435811. The reversal of 84435809 is 90853448.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 75603025 + 8832784 = 8695^2 + 2972^2 .

It is a cyclic number.

It is not a de Polignac number, because 84435809 - 2¹² = 84431713 is a prime.

Together with 84435811, 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 (84435409) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42217904 + 42217905.

It is an arithmetic number, because the mean of its divisors is an integer number (42217905).

Almost surely, 2^84435809 is an apocalyptic number.

It is an amenable number.

84435809 is a deficient number, since it is larger than the sum of its proper divisors (1).

84435809 is an equidigital number, since it uses as much as digits as its factorization.

84435809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 138240, while the sum is 41.

The square root of 84435809 is about 9188.8959619750. The cubic root of 84435809 is about 438.7080023004.

The spelling of 84435809 in words is "eighty-four million, four hundred thirty-five thousand, eight hundred nine".