9999820 has 24 divisors (see below), whose sum is σ = 21268800. Its totient is φ = 3948672.

The previous prime is 9999761. The next prime is 9999823. The reversal of 9999820 is 289999.

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 (9999823) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1585 + ... + 4744.

It is an arithmetic number, because the mean of its divisors is an integer number (886200).

Almost surely, 2^9999820 is an apocalyptic number.

It is an amenable number.

9999820 is an abundant number, since it is smaller than the sum of its proper divisors (11268980).

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

9999820 is a wasteful number, since it uses less digits than its factorization.

9999820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6417 (or 6415 counting only the distinct ones).

The product of its (nonzero) digits is 104976, while the sum is 46.

The square root of 9999820 is about 3162.2491995414. The cubic root of 9999820 is about 215.4421763346.

The spelling of 9999820 in words is "nine million, nine hundred ninety-nine thousand, eight hundred twenty".