909090909 has 24 divisors (see below), whose sum is σ = 1350271104.
Its totient is φ = 589032000.
The previous prime is 909090859. The next prime is 909090911.
909090909 is nontrivially palindromic in base 10.
It is not a de Polignac number, because 909090909 - 213 = 909082717 is a prime.
It is an alternating number because its digits alternate between odd and even.
909090909 is an undulating number in base 10.
909090909 is a modest number, since divided by 90909 gives 909 as remainder.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (909090109) by changing a digit.
It is a Kaprekar number, because its square (826446280826446281) can be partitioned into two parts whose sum is 909090909.
It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 95454 + ... + 104544.
It is an arithmetic number, because the mean of its divisors is an integer number (56261296).
Almost surely, 2909090909 is an apocalyptic number.
It is an amenable number.
909090909 is a deficient number, since it is larger than the sum of its proper divisors (441180195).
909090909 is a wasteful number, since it uses less digits than its factorization.
909090909 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 9409 (or 9406 counting only the distinct ones).
The product of its (nonzero) digits is 59049, while the sum is 45.
The square root of 909090909 is about 30151.1344562688.
The cubic root of 909090909 is about 968.7293061192.
The spelling of 909090909 in words is "nine hundred nine million, ninety thousand, nine hundred nine".