Search a number
28404 = 2233263
BaseRepresentation
bin110111011110100
31102222000
412323310
51402104
6335300
7145545
oct67364
942860
1028404
111a382
1214530
13cc0c
14a4cc
158639
hex6ef4

28404 has 24 divisors (see below), whose sum is σ = 73920. Its totient is φ = 9432.

The previous prime is 28403. The next prime is 28409. The reversal of 28404 is 40482.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28403) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24 + ... + 239.

It is an arithmetic number, because the mean of its divisors is an integer number (3080).

228404 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28404, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36960).

28404 is an abundant number, since it is smaller than the sum of its proper divisors (45516).

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

28404 is a wasteful number, since it uses less digits than its factorization.

28404 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 276 (or 268 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 18.

The square root of 28404 is about 168.5348628623. The cubic root of 28404 is about 30.5112383560.

Adding to 28404 its reverse (40482), we get a palindrome (68886).

The spelling of 28404 in words is "twenty-eight thousand, four hundred four".