28021104 has 30 divisors (see below), whose sum is σ = 78420576. Its totient is φ = 9340320.

The previous prime is 28021093. The next prime is 28021109. The reversal of 28021104 is 40112082.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28021109) 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, 97152 + ... + 97439.

Almost surely, 2^28021104 is an apocalyptic number.

28021104 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

28021104 is an abundant number, since it is smaller than the sum of its proper divisors (50399472).

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

28021104 is a wasteful number, since it uses less digits than its factorization.

28021104 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 194605 (or 194596 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

The square root of 28021104 is about 5293.4963870773. The cubic root of 28021104 is about 303.7351687114.

Adding to 28021104 its reverse (40112082), we get a palindrome (68133186).

The spelling of 28021104 in words is "twenty-eight million, twenty-one thousand, one hundred four".