21228838 has 16 divisors (see below), whose sum is σ = 32634000. Its totient is φ = 10354176.

The previous prime is 21228829. The next prime is 21228847. The reversal of 21228838 is 83882212.

It is an interprime number because it is at equal distance from previous prime (21228829) and next prime (21228847).

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 13413 + ... + 14911.

It is an arithmetic number, because the mean of its divisors is an integer number (2039625).

Almost surely, 2^21228838 is an apocalyptic number.

21228838 is a deficient number, since it is larger than the sum of its proper divisors (11405162).

21228838 is a wasteful number, since it uses less digits than its factorization.

21228838 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1671.

The product of its digits is 12288, while the sum is 34.

The square root of 21228838 is about 4607.4763157286. The cubic root of 21228838 is about 276.8909370067.

The spelling of 21228838 in words is "twenty-one million, two hundred twenty-eight thousand, eight hundred thirty-eight".