20217228 has 12 divisors (see below), whose sum is σ = 47173560. Its totient is φ = 6739072.

The previous prime is 20217209. The next prime is 20217229. The reversal of 20217228 is 82271202.

It is a happy number.

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 = 20217198 and 20217207.

It is not an unprimeable number, because it can be changed into a prime (20217229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 842373 + ... + 842396.

It is an arithmetic number, because the mean of its divisors is an integer number (3931130).

Almost surely, 2^20217228 is an apocalyptic number.

It is an amenable number.

20217228 is an abundant number, since it is smaller than the sum of its proper divisors (26956332).

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

20217228 is a wasteful number, since it uses less digits than its factorization.

20217228 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1684776 (or 1684774 counting only the distinct ones).

The product of its (nonzero) digits is 896, while the sum is 24.

The square root of 20217228 is about 4496.3571922168. The cubic root of 20217228 is about 272.4209708261.

The spelling of 20217228 in words is "twenty million, two hundred seventeen thousand, two hundred twenty-eight".