20911228 has 12 divisors (see below), whose sum is σ = 39409720. Its totient is φ = 9651312.

The previous prime is 20911223. The next prime is 20911243. The reversal of 20911228 is 82211902.

It is a hoax number, since the sum of its digits (25) coincides with the sum of the digits of its distinct prime factors.

It is a nialpdrome in base 13.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20911223) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 201018 + ... + 201121.

Almost surely, 2^20911228 is an apocalyptic number.

It is an amenable number.

20911228 is a deficient number, since it is larger than the sum of its proper divisors (18498492).

20911228 is a wasteful number, since it uses less digits than its factorization.

20911228 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 402156 (or 402154 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 25.

The square root of 20911228 is about 4572.8796179213. The cubic root of 20911228 is about 275.5031142497.

The spelling of 20911228 in words is "twenty million, nine hundred eleven thousand, two hundred twenty-eight".