28001688 has 128 divisors (see below), whose sum is σ = 84672000. Its totient is φ = 7603200.

The previous prime is 28001671. The next prime is 28001693. The reversal of 28001688 is 88610082.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 140613 + ... + 140811.

It is an arithmetic number, because the mean of its divisors is an integer number (661500).

Almost surely, 2^28001688 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 28001688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42336000).

28001688 is an abundant number, since it is smaller than the sum of its proper divisors (56670312).

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

28001688 is a wasteful number, since it uses less digits than its factorization.

28001688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 273 (or 269 counting only the distinct ones).

The product of its (nonzero) digits is 6144, while the sum is 33.

The square root of 28001688 is about 5291.6621207330. The cubic root of 28001688 is about 303.6649991628.

The spelling of 28001688 in words is "twenty-eight million, one thousand, six hundred eighty-eight".