28011800 has 48 divisors (see below), whose sum is σ = 65520360. Its totient is φ = 11137280.

The previous prime is 28011799. The next prime is 28011803. The reversal of 28011800 is 811082.

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 (28011803) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 45092 + ... + 45708.

Almost surely, 2^28011800 is an apocalyptic number.

28011800 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 28011800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32760180).

28011800 is an abundant number, since it is smaller than the sum of its proper divisors (37508560).

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

28011800 is a wasteful number, since it uses less digits than its factorization.

28011800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 860 (or 851 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 20.

The square root of 28011800 is about 5292.6174998766. The cubic root of 28011800 is about 303.7015480418.

Adding to 28011800 its reverse (811082), we get a palindrome (28822882).

The spelling of 28011800 in words is "twenty-eight million, eleven thousand, eight hundred".