999986609 has 2 divisors, whose sum is σ = 999986610. Its totient is φ = 999986608.

The previous prime is 999986599. The next prime is 999986627. The reversal of 999986609 is 906689999.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 569299600 + 430687009 = 23860^2 + 20753^2 .

It is a cyclic number.

It is not a de Polignac number, because 999986609 - 2¹² = 999982513 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (999986639) 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, 499993304 + 499993305.

It is an arithmetic number, because the mean of its divisors is an integer number (499993305).

Almost surely, 2^999986609 is an apocalyptic number.

It is an amenable number.

999986609 is a deficient number, since it is larger than the sum of its proper divisors (1).

999986609 is an equidigital number, since it uses as much as digits as its factorization.

999986609 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 17006112, while the sum is 65.

The square root of 999986609 is about 31622.5648706742. The cubic root of 999986609 is about 999.9955363134.

The spelling of 999986609 in words is "nine hundred ninety-nine million, nine hundred eighty-six thousand, six hundred nine".