900000209 has 2 divisors, whose sum is σ = 900000210. Its totient is φ = 900000208.

The previous prime is 900000197. The next prime is 900000221. The reversal of 900000209 is 902000009.

It is a balanced prime because it is at equal distance from previous prime (900000197) and next prime (900000221).

It can be written as a sum of positive squares in only one way, i.e., 835036609 + 64963600 = 28897^2 + 8060^2 .

It is an emirp because it is prime and its reverse (902000009) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 900000209 - 2²⁸ = 631564753 is a prime.

It is not a weakly prime, because it can be changed into another prime (900000709) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 450000104 + 450000105.

It is an arithmetic number, because the mean of its divisors is an integer number (450000105).

Almost surely, 2^900000209 is an apocalyptic number.

It is an amenable number.

900000209 is a deficient number, since it is larger than the sum of its proper divisors (1).

900000209 is an equidigital number, since it uses as much as digits as its factorization.

900000209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 162, while the sum is 20.

The square root of 900000209 is about 30000.0034833331. The cubic root of 900000209 is about 965.4894593417.

The spelling of 900000209 in words is "nine hundred million, two hundred nine", and thus it is an aban number.