85505509 has 2 divisors, whose sum is σ = 85505510. Its totient is φ = 85505508.

The previous prime is 85505507. The next prime is 85505551. The reversal of 85505509 is 90550558.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 78269409 + 7236100 = 8847^2 + 2690^2 .

It is a cyclic number.

It is not a de Polignac number, because 85505509 - 2¹ = 85505507 is a prime.

It is a super-2 number, since 2×85505509² = 14622384138698162, which contains 22 as substring.

Together with 85505507, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (85505501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42752754 + 42752755.

It is an arithmetic number, because the mean of its divisors is an integer number (42752755).

Almost surely, 2^85505509 is an apocalyptic number.

It is an amenable number.

85505509 is a deficient number, since it is larger than the sum of its proper divisors (1).

85505509 is an equidigital number, since it uses as much as digits as its factorization.

85505509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 45000, while the sum is 37.

The square root of 85505509 is about 9246.9188922581. The cubic root of 85505509 is about 440.5528673498.

The spelling of 85505509 in words is "eighty-five million, five hundred five thousand, five hundred nine".