28393638 has 192 divisors, whose sum is σ = 82736640. Its totient is φ = 6386688.

The previous prime is 28393633. The next prime is 28393649. The reversal of 28393638 is 83639382.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a self number, because there is not a number n which added to its sum of digits gives 28393638.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28393633) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 1234495 + ... + 1234517.

It is an arithmetic number, because the mean of its divisors is an integer number (430920).

Almost surely, 2^28393638 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28393638, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41368320).

28393638 is an abundant number, since it is smaller than the sum of its proper divisors (54343002).

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

28393638 is a wasteful number, since it uses less digits than its factorization.

28393638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91 (or 84 counting only the distinct ones).

The product of its digits is 186624, while the sum is 42.

The square root of 28393638 is about 5328.5681003437. The cubic root of 28393638 is about 305.0752765911.

The spelling of 28393638 in words is "twenty-eight million, three hundred ninety-three thousand, six hundred thirty-eight".