90000009 has 12 divisors (see below), whose sum is σ = 141818352. Its totient is φ = 54545400.
The previous prime is 89999999. The next prime is 90000049.
90000009 is nontrivially palindromic in base 10.
It is not a de Polignac number, because 90000009 - 216 = 89934473 is a prime.
It is a junction number, because it is equal to n+sod(n) for n = 89999946 and 90000000.
It is not an unprimeable number, because it can be changed into a prime (90000049) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (13) of ones.
It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 454447 + ... + 454644.
It is an arithmetic number, because the mean of its divisors is an integer number (11818196).
Almost surely, 290000009 is an apocalyptic number.
90000009 is a gapful number since it is divisible by the number (99) formed by its first and last digit.
It is an amenable number.
90000009 is a deficient number, since it is larger than the sum of its proper divisors (51818343).
90000009 is a wasteful number, since it uses less digits than its factorization.
90000009 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 909108 (or 909105 counting only the distinct ones).
The product of its (nonzero) digits is 81, while the sum is 18.
The square root of 90000009 is about 9486.8334548468. The cubic root of 90000009 is about 448.1404895937.
It can be divided in two parts, 9000000 and 9, that multiplied together give a square (81000000 = 90002).
The spelling of 90000009 in words is "ninety million, nine", and thus it is an aban number and an uban number.
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