21828216 has 32 divisors (see below), whose sum is σ = 56332800. Its totient is φ = 7041120.

The previous prime is 21828199. The next prime is 21828217. The reversal of 21828216 is 61282812.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21828217) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 13926 + ... + 15413.

It is an arithmetic number, because the mean of its divisors is an integer number (1760400).

Almost surely, 2^21828216 is an apocalyptic number.

It is an amenable number.

21828216 is an abundant number, since it is smaller than the sum of its proper divisors (34504584).

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

21828216 is a wasteful number, since it uses less digits than its factorization.

21828216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29379 (or 29375 counting only the distinct ones).

The product of its digits is 3072, while the sum is 30.

The square root of 21828216 is about 4672.0676364967. The cubic root of 21828216 is about 279.4727151444.

The spelling of 21828216 in words is "twenty-one million, eight hundred twenty-eight thousand, two hundred sixteen".