855209609 has 2 divisors, whose sum is σ = 855209610. Its totient is φ = 855209608.

The previous prime is 855209581. The next prime is 855209629. The reversal of 855209609 is 906902558.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 852640000 + 2569609 = 29200^2 + 1603^2 .

It is a cyclic number.

It is not a de Polignac number, because 855209609 - 2⁸ = 855209353 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 855209609.

It is not a weakly prime, because it can be changed into another prime (855209629) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 427604804 + 427604805.

It is an arithmetic number, because the mean of its divisors is an integer number (427604805).

Almost surely, 2^855209609 is an apocalyptic number.

It is an amenable number.

855209609 is a deficient number, since it is larger than the sum of its proper divisors (1).

855209609 is an equidigital number, since it uses as much as digits as its factorization.

855209609 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 194400, while the sum is 44.

The square root of 855209609 is about 29243.9670530522. The cubic root of 855209609 is about 949.1995506790.

The spelling of 855209609 in words is "eight hundred fifty-five million, two hundred nine thousand, six hundred nine".