21939284 has 24 divisors (see below), whose sum is σ = 39549888. Its totient is φ = 10644480.

The previous prime is 21939277. The next prime is 21939361. The reversal of 21939284 is 48293912.

It is a congruent number.

It is an unprimeable number.

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, 18452 + ... + 19604.

It is an arithmetic number, because the mean of its divisors is an integer number (1647912).

Almost surely, 2^21939284 is an apocalyptic number.

It is an amenable number.

21939284 is a deficient number, since it is larger than the sum of its proper divisors (17610604).

21939284 is a wasteful number, since it uses less digits than its factorization.

21939284 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1295 (or 1293 counting only the distinct ones).

The product of its digits is 31104, while the sum is 38.

The square root of 21939284 is about 4683.9389406780. The cubic root of 21939284 is about 279.9459249316.

The spelling of 21939284 in words is "twenty-one million, nine hundred thirty-nine thousand, two hundred eighty-four".