9987209 has 2 divisors, whose sum is σ = 9987210. Its totient is φ = 9987208.

The previous prime is 9987191. The next prime is 9987247. The reversal of 9987209 is 9027899.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6553600 + 3433609 = 2560^2 + 1853^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-9987209 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 9987209.

It is not a weakly prime, because it can be changed into another prime (9987709) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4993604 + 4993605.

It is an arithmetic number, because the mean of its divisors is an integer number (4993605).

Almost surely, 2^9987209 is an apocalyptic number.

It is an amenable number.

9987209 is a deficient number, since it is larger than the sum of its proper divisors (1).

9987209 is an equidigital number, since it uses as much as digits as its factorization.

9987209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 81648, while the sum is 44.

The square root of 9987209 is about 3160.2545783528. The cubic root of 9987209 is about 215.3515718964.

The spelling of 9987209 in words is "nine million, nine hundred eighty-seven thousand, two hundred nine".