20091228 has 12 divisors (see below), whose sum is σ = 46879560. Its totient is φ = 6697072.

The previous prime is 20091179. The next prime is 20091233. The reversal of 20091228 is 82219002.

It is a tau number, because it is divible by the number of its divisors (12).

It is a junction number, because it is equal to n+sod(n) for n = 20091198 and 20091207.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 837123 + ... + 837146.

It is an arithmetic number, because the mean of its divisors is an integer number (3906630).

Almost surely, 2^20091228 is an apocalyptic number.

It is an amenable number.

20091228 is an abundant number, since it is smaller than the sum of its proper divisors (26788332).

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

20091228 is a wasteful number, since it uses less digits than its factorization.

20091228 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1674276 (or 1674274 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 24.

The square root of 20091228 is about 4482.3239508094. The cubic root of 20091228 is about 271.8538538712.

The spelling of 20091228 in words is "twenty million, ninety-one thousand, two hundred twenty-eight".