28081900 has 108 divisors (see below), whose sum is σ = 77479416. Its totient is φ = 8736000.

The previous prime is 28081897. The next prime is 28081901. The reversal of 28081900 is 918082.

It is a super-2 number, since 2×28081900² = 1577186215220000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is not an unprimeable number, because it can be changed into a prime (28081901) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 53640 + ... + 54160.

It is an arithmetic number, because the mean of its divisors is an integer number (717402).

Almost surely, 2^28081900 is an apocalyptic number.

28081900 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 28081900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38739708).

28081900 is an abundant number, since it is smaller than the sum of its proper divisors (49397516).

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

28081900 is a wasteful number, since it uses less digits than its factorization.

28081900 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 560 (or 546 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 28.

The square root of 28081900 is about 5299.2357939612. The cubic root of 28081900 is about 303.9546764148.

Adding to 28081900 its reverse (918082), we get a palindrome (28999982).

The spelling of 28081900 in words is "twenty-eight million, eighty-one thousand, nine hundred".