9990991728 has 60 divisors (see below), whose sum is σ = 28208388000. Its totient is φ = 3300853248.

The previous prime is 9990991727. The next prime is 9990991741. The reversal of 9990991728 is 8271990999.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9990991721) 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, 290728 + ... + 323271.

It is an arithmetic number, because the mean of its divisors is an integer number (470139800).

Almost surely, 2^9990991728 is an apocalyptic number.

It is an amenable number.

9990991728 is an abundant number, since it is smaller than the sum of its proper divisors (18217396272).

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

9990991728 is a wasteful number, since it uses less digits than its factorization.

9990991728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 614126 (or 614117 counting only the distinct ones).

The product of its (nonzero) digits is 6613488, while the sum is 63.

The square root of 9990991728 is about 99954.9484918080. The cubic root of 9990991728 is about 2153.7875712224.

The spelling of 9990991728 in words is "nine billion, nine hundred ninety million, nine hundred ninety-one thousand, seven hundred twenty-eight".