9990728 has 24 divisors (see below), whose sum is σ = 20592390. Its totient is φ = 4540800.

The previous prime is 9990727. The next prime is 9990731. The reversal of 9990728 is 8270999.

It can be written as a sum of positive squares in only one way, i.e., 8305924 + 1684804 = 2882^2 + 1298^2 .

It is a Harshad number since it is a multiple of its sum of digits (44).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9990727) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4193 + ... + 6128.

Almost surely, 2^9990728 is an apocalyptic number.

It is an amenable number.

9990728 is an abundant number, since it is smaller than the sum of its proper divisors (10601662).

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

9990728 is a wasteful number, since it uses less digits than its factorization.

9990728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10349 (or 10334 counting only the distinct ones).

The product of its (nonzero) digits is 81648, while the sum is 44.

The square root of 9990728 is about 3160.8112882613. The cubic root of 9990728 is about 215.3768620181.

The spelling of 9990728 in words is "nine million, nine hundred ninety thousand, seven hundred twenty-eight".