999649728 has 336 divisors, whose sum is σ = 3697102080. Its totient is φ = 259269120.

The previous prime is 999649723. The next prime is 999649751. The reversal of 999649728 is 827946999.

999649728 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (336).

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (999649723) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1463275 + ... + 1463957.

It is an arithmetic number, because the mean of its divisors is an integer number (11003280).

Almost surely, 2^999649728 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 999649728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1848551040).

999649728 is an abundant number, since it is smaller than the sum of its proper divisors (2697452352).

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

999649728 is a wasteful number, since it uses less digits than its factorization.

999649728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 733 (or 706 counting only the distinct ones).

The product of its digits is 17635968, while the sum is 63.

The square root of 999649728 is about 31617.2378300192. The cubic root of 999649728 is about 999.8832290317.

The spelling of 999649728 in words is "nine hundred ninety-nine million, six hundred forty-nine thousand, seven hundred twenty-eight".