21984321 has 8 divisors (see below), whose sum is σ = 29482560. Its totient is φ = 14571152.

The previous prime is 21984307. The next prime is 21984329. The reversal of 21984321 is 12348912.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21984321 - 2⁶ = 21984257 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21984329) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20661 + ... + 21698.

It is an arithmetic number, because the mean of its divisors is an integer number (3685320).

Almost surely, 2^21984321 is an apocalyptic number.

It is an amenable number.

21984321 is a deficient number, since it is larger than the sum of its proper divisors (7498239).

21984321 is a wasteful number, since it uses less digits than its factorization.

21984321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42535.

The product of its digits is 3456, while the sum is 30.

The square root of 21984321 is about 4688.7440749096. The cubic root of 21984321 is about 280.1373518298.

The spelling of 21984321 in words is "twenty-one million, nine hundred eighty-four thousand, three hundred twenty-one".