28581100 has 36 divisors (see below), whose sum is σ = 63542808. Its totient is φ = 11152000.

The previous prime is 28581089. The next prime is 28581103. The reversal of 28581100 is 118582.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28581103) 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, 615 + ... + 7585.

It is an arithmetic number, because the mean of its divisors is an integer number (1765078).

Almost surely, 2^28581100 is an apocalyptic number.

28581100 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 28581100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31771404).

28581100 is an abundant number, since it is smaller than the sum of its proper divisors (34961708).

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

28581100 is a wasteful number, since it uses less digits than its factorization.

28581100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7026 (or 7019 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 25.

The square root of 28581100 is about 5346.1294410068. The cubic root of 28581100 is about 305.7451991998.

Adding to 28581100 its reverse (118582), we get a palindrome (28699682).

The spelling of 28581100 in words is "twenty-eight million, five hundred eighty-one thousand, one hundred".