9899840 has 28 divisors (see below), whose sum is σ = 23574756. Its totient is φ = 3959808.

The previous prime is 9899833. The next prime is 9899861. The reversal of 9899840 is 489989.

It can be written as a sum of positive squares in 2 ways, for example, as 2238016 + 7661824 = 1496^2 + 2768^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15149 + ... + 15788.

Almost surely, 2^9899840 is an apocalyptic number.

It is an amenable number.

9899840 is an abundant number, since it is smaller than the sum of its proper divisors (13674916).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

9899840 is a wasteful number, since it uses less digits than its factorization.

9899840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30954 (or 30944 counting only the distinct ones).

The product of its (nonzero) digits is 186624, while the sum is 47.

The square root of 9899840 is about 3146.4011187387. The cubic root of 9899840 is about 214.7217601392.

The spelling of 9899840 in words is "nine million, eight hundred ninety-nine thousand, eight hundred forty".