28638320 has 80 divisors (see below), whose sum is σ = 71245440. Its totient is φ = 10674432.

The previous prime is 28638317. The next prime is 28638359. The reversal of 28638320 is 2383682.

It is a happy number.

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 polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 126047 + ... + 126273.

It is an arithmetic number, because the mean of its divisors is an integer number (890568).

Almost surely, 2^28638320 is an apocalyptic number.

28638320 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 28638320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35622720).

28638320 is an abundant number, since it is smaller than the sum of its proper divisors (42607120).

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

28638320 is a wasteful number, since it uses less digits than its factorization.

28638320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 342 (or 336 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 32.

The square root of 28638320 is about 5351.4783004325. The cubic root of 28638320 is about 305.9490994266.

The spelling of 28638320 in words is "twenty-eight million, six hundred thirty-eight thousand, three hundred twenty".