28001680 has 80 divisors (see below), whose sum is σ = 76852224. Its totient is φ = 9285120.

The previous prime is 28001671. The next prime is 28001693. The reversal of 28001680 is 8610082.

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16554 + ... + 18166.

Almost surely, 2^28001680 is an apocalyptic number.

28001680 is a gapful number since it is divisible by the number (20) 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 28001680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38426112).

28001680 is an abundant number, since it is smaller than the sum of its proper divisors (48850544).

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

28001680 is a wasteful number, since it uses less digits than its factorization.

28001680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1664 (or 1658 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 25.

The square root of 28001680 is about 5291.6613648267. The cubic root of 28001680 is about 303.6649702441.

The spelling of 28001680 in words is "twenty-eight million, one thousand, six hundred eighty".