20811228 has 24 divisors (see below), whose sum is σ = 50671488. Its totient is φ = 6635376.

The previous prime is 20811227. The next prime is 20811229. The reversal of 20811228 is 82211802.

It is an interprime number because it is at equal distance from previous prime (20811227) and next prime (20811229).

It is a junction number, because it is equal to n+sod(n) for n = 20811198 and 20811207.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20811227) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 37426 + ... + 37977.

It is an arithmetic number, because the mean of its divisors is an integer number (2111312).

Almost surely, 2^20811228 is an apocalyptic number.

It is an amenable number.

20811228 is an abundant number, since it is smaller than the sum of its proper divisors (29860260).

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

20811228 is a wasteful number, since it uses less digits than its factorization.

20811228 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 75433 (or 75431 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 24.

The square root of 20811228 is about 4561.9324852523. The cubic root of 20811228 is about 275.0632493635.

The spelling of 20811228 in words is "twenty million, eight hundred eleven thousand, two hundred twenty-eight".