999635009 has 2 divisors, whose sum is σ = 999635010. Its totient is φ = 999635008.

The previous prime is 999634991. The next prime is 999635023. The reversal of 999635009 is 900536999.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 574656784 + 424978225 = 23972^2 + 20615^2 .

It is an emirp because it is prime and its reverse (900536999) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 999635009 - 2²⁴ = 982857793 is a prime.

It is not a weakly prime, because it can be changed into another prime (999635099) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499817504 + 499817505.

It is an arithmetic number, because the mean of its divisors is an integer number (499817505).

Almost surely, 2^999635009 is an apocalyptic number.

It is an amenable number.

999635009 is a deficient number, since it is larger than the sum of its proper divisors (1).

999635009 is an equidigital number, since it uses as much as digits as its factorization.

999635009 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 590490, while the sum is 50.

The square root of 999635009 is about 31617.0050605683. The cubic root of 999635009 is about 999.8783215283.

The spelling of 999635009 in words is "nine hundred ninety-nine million, six hundred thirty-five thousand, nine".