21183928 has 16 divisors (see below), whose sum is σ = 39788280. Its totient is φ = 10573728.

The previous prime is 21183923. The next prime is 21183931. The reversal of 21183928 is 82938112.

It is a junction number, because it is equal to n+sod(n) for n = 21183893 and 21183902.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21183923) 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, 3526 + ... + 7402.

Almost surely, 2^21183928 is an apocalyptic number.

It is an amenable number.

21183928 is a deficient number, since it is larger than the sum of its proper divisors (18604352).

21183928 is a wasteful number, since it uses less digits than its factorization.

21183928 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4566 (or 4562 counting only the distinct ones).

The product of its digits is 6912, while the sum is 34.

The square root of 21183928 is about 4602.6001347065. The cubic root of 21183928 is about 276.6955431868.

The spelling of 21183928 in words is "twenty-one million, one hundred eighty-three thousand, nine hundred twenty-eight".