90990109 has 6 divisors (see below), whose sum is σ = 105845694. Its totient is φ = 77991480.

The previous prime is 90990091. The next prime is 90990113. The reversal of 90990109 is 90109909.

It can be written as a sum of positive squares in only one way, i.e., 75951225 + 15038884 = 8715^2 + 3878^2 .

It is not a de Polignac number, because 90990109 - 2⁵ = 90990077 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (90994109) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 928422 + ... + 928519.

It is an arithmetic number, because the mean of its divisors is an integer number (17640949).

Almost surely, 2^90990109 is an apocalyptic number.

It is an amenable number.

90990109 is a deficient number, since it is larger than the sum of its proper divisors (14855585).

90990109 is a wasteful number, since it uses less digits than its factorization.

90990109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1856955 (or 1856948 counting only the distinct ones).

The product of its (nonzero) digits is 6561, while the sum is 37.

The square root of 90990109 is about 9538.8735708154. The cubic root of 90990109 is about 449.7778475492. Note that the first 3 decimals are identical.

The spelling of 90990109 in words is "ninety million, nine hundred ninety thousand, one hundred nine".