21869828 has 12 divisors (see below), whose sum is σ = 39592140. Its totient is φ = 10557792.

The previous prime is 21869821. The next prime is 21869839. The reversal of 21869828 is 82896812.

It can be written as a sum of positive squares in 2 ways, for example, as 14730244 + 7139584 = 3838^2 + 2672^2 .

It is not an unprimeable number, because it can be changed into a prime (21869821) 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 3 ways as a sum of consecutive naturals, for example, 94151 + ... + 94382.

It is an arithmetic number, because the mean of its divisors is an integer number (3299345).

Almost surely, 2^21869828 is an apocalyptic number.

It is an amenable number.

21869828 is a deficient number, since it is larger than the sum of its proper divisors (17722312).

21869828 is a wasteful number, since it uses less digits than its factorization.

21869828 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 188566 (or 188564 counting only the distinct ones).

The product of its digits is 110592, while the sum is 44.

The square root of 21869828 is about 4676.5187907246. The cubic root of 21869828 is about 279.6501924146.

The spelling of 21869828 in words is "twenty-one million, eight hundred sixty-nine thousand, eight hundred twenty-eight".