9978812720 has 20 divisors (see below), whose sum is σ = 23200739760. Its totient is φ = 3991525056.

The previous prime is 9978812719. The next prime is 9978812741. The reversal of 9978812720 is 272188799.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (20).

It is an unprimeable number.

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, 62367500 + ... + 62367659.

It is an arithmetic number, because the mean of its divisors is an integer number (1160036988).

Almost surely, 2^9978812720 is an apocalyptic number.

It is an amenable number.

9978812720 is an abundant number, since it is smaller than the sum of its proper divisors (13221927040).

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

9978812720 is a wasteful number, since it uses less digits than its factorization.

9978812720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 124735172 (or 124735166 counting only the distinct ones).

The product of its (nonzero) digits is 1016064, while the sum is 53.

The square root of 9978812720 is about 99894.0074278733. The cubic root of 9978812720 is about 2152.9120604784.

The spelling of 9978812720 in words is "nine billion, nine hundred seventy-eight million, eight hundred twelve thousand, seven hundred twenty".