28289664 has 96 divisors (see below), whose sum is σ = 87714900. Its totient is φ = 8699904.

The previous prime is 28289647. The next prime is 28289669. The reversal of 28289664 is 46698282.

It can be written as a sum of positive squares in 2 ways, for example, as 27123264 + 1166400 = 5208^2 + 1080^2 .

It is a tau number, because it is divible by the number of its divisors (96).

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

It is not an unprimeable number, because it can be changed into a prime (28289669) 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, 14032 + ... + 15920.

Almost surely, 2^28289664 is an apocalyptic number.

28289664 is a gapful number since it is divisible by the number (24) 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 28289664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43857450).

28289664 is an abundant number, since it is smaller than the sum of its proper divisors (59425236).

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

28289664 is a wasteful number, since it uses less digits than its factorization.

28289664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1922 (or 1907 counting only the distinct ones).

The product of its digits is 331776, while the sum is 45.

The square root of 28289664 is about 5318.8028728277. The cubic root of 28289664 is about 304.7024384471.

The spelling of 28289664 in words is "twenty-eight million, two hundred eighty-nine thousand, six hundred sixty-four".