90009905 has 4 divisors (see below), whose sum is σ = 108011892. Its totient is φ = 72007920.

The previous prime is 90009901. The next prime is 90009919. The reversal of 90009905 is 50990009.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 53479969 + 36529936 = 7313^2 + 6044^2 .

It is not a de Polignac number, because 90009905 - 2² = 90009901 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (90009901) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9000986 + ... + 9000995.

It is an arithmetic number, because the mean of its divisors is an integer number (27002973).

Almost surely, 2^90009905 is an apocalyptic number.

It is an amenable number.

90009905 is a deficient number, since it is larger than the sum of its proper divisors (18001987).

90009905 is a wasteful number, since it uses less digits than its factorization.

90009905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18001986.

The product of its (nonzero) digits is 3645, while the sum is 32.

The square root of 90009905 is about 9487.3550054797. The cubic root of 90009905 is about 448.1569141689.

The spelling of 90009905 in words is "ninety million, nine thousand, nine hundred five".