28105400 has 24 divisors (see below), whose sum is σ = 65345520. Its totient is φ = 11242080.

The previous prime is 28105397. The next prime is 28105409. The reversal of 28105400 is 450182.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28105409) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 70064 + ... + 70463.

It is an arithmetic number, because the mean of its divisors is an integer number (2722730).

Almost surely, 2^28105400 is an apocalyptic number.

28105400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28105400 is an abundant number, since it is smaller than the sum of its proper divisors (37240120).

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

28105400 is a wasteful number, since it uses less digits than its factorization.

28105400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 140543 (or 140534 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 20.

The square root of 28105400 is about 5301.4526311191. The cubic root of 28105400 is about 304.0394397122.

Adding to 28105400 its reverse (450182), we get a palindrome (28555582).

The spelling of 28105400 in words is "twenty-eight million, one hundred five thousand, four hundred".