28000028 has 24 divisors (see below), whose sum is σ = 56560224. Its totient is φ = 11880000.

The previous prime is 28000019. The next prime is 28000031. The reversal of 28000028 is 82000082.

28000028 = 1997² + 1998² + ... + 2003².

It is a junction number, because it is equal to n+sod(n) for n = 27999973 and 28000009.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2123 + ... + 7778.

It is an arithmetic number, because the mean of its divisors is an integer number (2356676).

Almost surely, 2^28000028 is an apocalyptic number.

28000028 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

28000028 is an abundant number, since it is smaller than the sum of its proper divisors (28560196).

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

28000028 is a wasteful number, since it uses less digits than its factorization.

28000028 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10013 (or 10011 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 20.

The square root of 28000028 is about 5291.5052678798. The cubic root of 28000028 is about 303.6589984072.

It can be divided in two parts, 280000 and 28, that multiplied together give a square (7840000 = 2800²).

The spelling of 28000028 in words is "twenty-eight million, twenty-eight", and thus it is an aban number and an uban number.