900000009 has 12 divisors (see below), whose sum is σ = 1376470836. Its totient is φ = 564705792.

The previous prime is 899999963. The next prime is 900000011.

900000009 is nontrivially palindromic in base 10.

It can be written as a sum of positive squares in 2 ways, for example, as 700766784 + 199233225 = 26472^2 + 14115^2 .

It is not a de Polignac number, because 900000009 - 2¹¹ = 899997961 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 899999937 and 900000000.

It is not an unprimeable number, because it can be changed into a prime (900000209) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2941024 + ... + 2941329.

It is an arithmetic number, because the mean of its divisors is an integer number (114705903).

Almost surely, 2^900000009 is an apocalyptic number.

It is an amenable number.

900000009 is a deficient number, since it is larger than the sum of its proper divisors (476470827).

900000009 is a wasteful number, since it uses less digits than its factorization.

900000009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5882376 (or 5882373 counting only the distinct ones).

The product of its (nonzero) digits is 81, while the sum is 18.

The square root of 900000009 is about 30000.0001500000. Note that the first 3 decimals coincide. The cubic root of 900000009 is about 965.4893878239.

It can be divided in two parts, 90000000 and 9, that added together give a palindrome (90000009).

The spelling of 900000009 in words is "nine hundred million, nine", and thus it is an aban number.