9928638720 has 1728 divisors, whose sum is σ = 49324826880. Its totient is φ = 1857945600.

The previous prime is 9928638703. The next prime is 9928638721. The reversal of 9928638720 is 278368299.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (1728).

It is a super-3 number, since 3×9928638720³ (a number of 31 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (9928638721) by changing a digit.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 242161900 + ... + 242161940.

It is an arithmetic number, because the mean of its divisors is an integer number (28544460).

Almost surely, 2^9928638720 is an apocalyptic number.

9928638720 is a gapful number since it is divisible by the number (90) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 9928638720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24662413440).

9928638720 is an abundant number, since it is smaller than the sum of its proper divisors (39396188160).

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

9928638720 is a wasteful number, since it uses less digits than its factorization.

9928638720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 109 (or 82 counting only the distinct ones).

The product of its (nonzero) digits is 2612736, while the sum is 54.

The square root of 9928638720 is about 99642.5547645182. The cubic root of 9928638720 is about 2149.2976772192.

The spelling of 9928638720 in words is "nine billion, nine hundred twenty-eight million, six hundred thirty-eight thousand, seven hundred twenty".