9999920 has 60 divisors (see below), whose sum is σ = 27056304. Its totient is φ = 3427200.

The previous prime is 9999907. The next prime is 9999929. The reversal of 9999920 is 299999.

It is a happy number.

It is a nialpdrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (9999929) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2645 + ... + 5195.

Almost surely, 2^9999920 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 9999920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (13528152).

9999920 is an abundant number, since it is smaller than the sum of its proper divisors (17056384).

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

9999920 is a wasteful number, since it uses less digits than its factorization.

9999920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2578 (or 2565 counting only the distinct ones).

The product of its (nonzero) digits is 118098, while the sum is 47.

The square root of 9999920 is about 3162.2650110324. The cubic root of 9999920 is about 215.4428944857.

The spelling of 9999920 in words is "nine million, nine hundred ninety-nine thousand, nine hundred twenty".