869247209 has 2 divisors, whose sum is σ = 869247210. Its totient is φ = 869247208.

The previous prime is 869247199. The next prime is 869247217. The reversal of 869247209 is 902742968.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 814531600 + 54715609 = 28540^2 + 7397^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-869247209 is a prime.

It is not a weakly prime, because it can be changed into another prime (869247229) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 434623604 + 434623605.

It is an arithmetic number, because the mean of its divisors is an integer number (434623605).

Almost surely, 2^869247209 is an apocalyptic number.

It is an amenable number.

869247209 is a deficient number, since it is larger than the sum of its proper divisors (1).

869247209 is an equidigital number, since it uses as much as digits as its factorization.

869247209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 435456, while the sum is 47.

The square root of 869247209 is about 29482.9986432859. The cubic root of 869247209 is about 954.3648487217.

The spelling of 869247209 in words is "eight hundred sixty-nine million, two hundred forty-seven thousand, two hundred nine".