28643664 has 80 divisors (see below), whose sum is σ = 85248512. Its totient is φ = 8118144.

The previous prime is 28643653. The next prime is 28643669. The reversal of 28643664 is 46634682.

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 (28643669) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 54507 + ... + 55029.

Almost surely, 2^28643664 is an apocalyptic number.

28643664 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 28643664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42624256).

28643664 is an abundant number, since it is smaller than the sum of its proper divisors (56604848).

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

28643664 is a wasteful number, since it uses less digits than its factorization.

28643664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 704 (or 698 counting only the distinct ones).

The product of its digits is 165888, while the sum is 39.

The square root of 28643664 is about 5351.9775784284. The cubic root of 28643664 is about 305.9681285956.

The spelling of 28643664 in words is "twenty-eight million, six hundred forty-three thousand, six hundred sixty-four".