999988609 has 2 divisors, whose sum is σ = 999988610. Its totient is φ = 999988608.

The previous prime is 999988589. The next prime is 999988679. The reversal of 999988609 is 906889999.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 930433009 + 69555600 = 30503^2 + 8340^2 .

It is a cyclic number.

It is not a de Polignac number, because 999988609 - 2¹³ = 999980417 is a prime.

It is not a weakly prime, because it can be changed into another prime (999988679) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499994304 + 499994305.

It is an arithmetic number, because the mean of its divisors is an integer number (499994305).

Almost surely, 2^999988609 is an apocalyptic number.

It is an amenable number.

999988609 is a deficient number, since it is larger than the sum of its proper divisors (1).

999988609 is an equidigital number, since it uses as much as digits as its factorization.

999988609 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 22674816, while the sum is 67.

The square root of 999988609 is about 31622.5964936468. The cubic root of 999988609 is about 999.9962029856.

The spelling of 999988609 in words is "nine hundred ninety-nine million, nine hundred eighty-eight thousand, six hundred nine".