21584428 has 6 divisors (see below), whose sum is σ = 37772756. Its totient is φ = 10792212.

The previous prime is 21584417. The next prime is 21584461. The reversal of 21584428 is 82448512.

It is a junction number, because it is equal to n+sod(n) for n = 21584393 and 21584402.

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 as a sum of consecutive naturals, namely, 2698050 + ... + 2698057.

Almost surely, 2^21584428 is an apocalyptic number.

It is an amenable number.

21584428 is a deficient number, since it is larger than the sum of its proper divisors (16188328).

21584428 is a wasteful number, since it uses less digits than its factorization.

21584428 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5396111 (or 5396109 counting only the distinct ones).

The product of its digits is 20480, while the sum is 34.

The square root of 21584428 is about 4645.9044329388. The cubic root of 21584428 is about 278.4283890932.

The spelling of 21584428 in words is "twenty-one million, five hundred eighty-four thousand, four hundred twenty-eight".