90009 has 12 divisors (see below), whose sum is σ = 132756. Its totient is φ = 58752.
The previous prime is 90007. The next prime is 90011.
90009 is nontrivially palindromic in base 10.
It is an interprime number because it is at equal distance from previous prime (90007) and next prime (90011).
It can be written as a sum of positive squares in 2 ways, for example, as 51984 + 38025 = 228^2 + 195^2 .
It is not a de Polignac number, because 90009 - 21 = 90007 is a prime.
90009 is a lucky number.
It is a junction number, because it is equal to n+sod(n) for n = 89973 and 90000.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (90001) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (11) of ones.
It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 589 + ... + 725.
It is an arithmetic number, because the mean of its divisors is an integer number (11063).
290009 is an apocalyptic number.
It is an amenable number.
90009 is a deficient number, since it is larger than the sum of its proper divisors (42747).
90009 is a wasteful number, since it uses less digits than its factorization.
90009 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 216 (or 213 counting only the distinct ones).
The product of its (nonzero) digits is 81, while the sum is 18.
The square root of 90009 is about 300.0149996250. The cubic root of 90009 is about 44.8155412174.
It can be divided in two parts, 9000 and 9, that added together give a palindrome (9009).
The spelling of 90009 in words is "ninety thousand, nine".
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