999997309 has 2 divisors, whose sum is σ = 999997310. Its totient is φ = 999997308.

The previous prime is 999997301. The next prime is 999997331. The reversal of 999997309 is 903799999.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 661621284 + 338376025 = 25722^2 + 18395^2 .

It is a cyclic number.

It is not a de Polignac number, because 999997309 - 2³ = 999997301 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (999997301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499998654 + 499998655.

It is an arithmetic number, because the mean of its divisors is an integer number (499998655).

Almost surely, 2^999997309 is an apocalyptic number.

It is an amenable number.

999997309 is a deficient number, since it is larger than the sum of its proper divisors (1).

999997309 is an equidigital number, since it uses as much as digits as its factorization.

999997309 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 11160261, while the sum is 64.

The square root of 999997309 is about 31622.7340532093. The cubic root of 999997309 is about 999.9991029992. Note that the first 3 decimals are identical.

The spelling of 999997309 in words is "nine hundred ninety-nine million, nine hundred ninety-seven thousand, three hundred nine".