855398209 has 2 divisors, whose sum is σ = 855398210. Its totient is φ = 855398208.

The previous prime is 855398207. The next prime is 855398233. The reversal of 855398209 is 902893558.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 641507584 + 213890625 = 25328^2 + 14625^2 .

It is a cyclic number.

It is not a de Polignac number, because 855398209 - 2¹ = 855398207 is a prime.

Together with 855398207, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (855398207) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 427699104 + 427699105.

It is an arithmetic number, because the mean of its divisors is an integer number (427699105).

Almost surely, 2^855398209 is an apocalyptic number.

It is an amenable number.

855398209 is a deficient number, since it is larger than the sum of its proper divisors (1).

855398209 is an equidigital number, since it uses as much as digits as its factorization.

855398209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 777600, while the sum is 49.

The square root of 855398209 is about 29247.1914720029. The cubic root of 855398209 is about 949.2693214406.

The spelling of 855398209 in words is "eight hundred fifty-five million, three hundred ninety-eight thousand, two hundred nine".