9902905 has 4 divisors (see below), whose sum is σ = 11883492. Its totient is φ = 7922320.

The previous prime is 9902897. The next prime is 9902909. The reversal of 9902905 is 5092099.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5092099 = 599 ⋅8501.

It can be written as a sum of positive squares in 2 ways, for example, as 1212201 + 8690704 = 1101^2 + 2948^2 .

It is not a de Polignac number, because 9902905 - 2³ = 9902897 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 (9902909) 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 3 ways as a sum of consecutive naturals, for example, 990286 + ... + 990295.

It is an arithmetic number, because the mean of its divisors is an integer number (2970873).

Almost surely, 2^9902905 is an apocalyptic number.

It is an amenable number.

9902905 is a deficient number, since it is larger than the sum of its proper divisors (1980587).

9902905 is a wasteful number, since it uses less digits than its factorization.

9902905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1980586.

The product of its (nonzero) digits is 7290, while the sum is 34.

The square root of 9902905 is about 3146.8881454542. Note that the first 3 decimals coincide. The cubic root of 9902905 is about 214.7439172073.

The spelling of 9902905 in words is "nine million, nine hundred two thousand, nine hundred five".