85905509 has 2 divisors, whose sum is σ = 85905510. Its totient is φ = 85905508.

The previous prime is 85905493. The next prime is 85905551. The reversal of 85905509 is 90550958.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 81993025 + 3912484 = 9055^2 + 1978^2 .

It is a cyclic number.

It is not a de Polignac number, because 85905509 - 2⁴ = 85905493 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (85905409) 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, 42952754 + 42952755.

It is an arithmetic number, because the mean of its divisors is an integer number (42952755).

Almost surely, 2^85905509 is an apocalyptic number.

It is an amenable number.

85905509 is a deficient number, since it is larger than the sum of its proper divisors (1).

85905509 is an equidigital number, since it uses as much as digits as its factorization.

85905509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 81000, while the sum is 41.

The square root of 85905509 is about 9268.5224820356. The cubic root of 85905509 is about 441.2387766354.

The spelling of 85905509 in words is "eighty-five million, nine hundred five thousand, five hundred nine".