85704209 has 2 divisors, whose sum is σ = 85704210. Its totient is φ = 85704208.

The previous prime is 85704197. The next prime is 85704211. The reversal of 85704209 is 90240758.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 67240000 + 18464209 = 8200^2 + 4297^2 .

It is a cyclic number.

It is not a de Polignac number, because 85704209 - 2¹² = 85700113 is a prime.

It is a super-2 number, since 2×85704209² = 14690422880631362, which contains 22 as substring.

Together with 85704211, 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 (85704239) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42852104 + 42852105.

It is an arithmetic number, because the mean of its divisors is an integer number (42852105).

Almost surely, 2^85704209 is an apocalyptic number.

It is an amenable number.

85704209 is a deficient number, since it is larger than the sum of its proper divisors (1).

85704209 is an equidigital number, since it uses as much as digits as its factorization.

85704209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 20160, while the sum is 35.

The square root of 85704209 is about 9257.6567769604. The cubic root of 85704209 is about 440.8938595485.

The spelling of 85704209 in words is "eighty-five million, seven hundred four thousand, two hundred nine".