21329924 has 48 divisors (see below), whose sum is σ = 48577536. Its totient is φ = 7946400.

The previous prime is 21329923. The next prime is 21329927. The reversal of 21329924 is 42992312.

It is not an unprimeable number, because it can be changed into a prime (21329923) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5579 + ... + 8589.

It is an arithmetic number, because the mean of its divisors is an integer number (1012032).

Almost surely, 2^21329924 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21329924, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24288768).

21329924 is an abundant number, since it is smaller than the sum of its proper divisors (27247612).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21329924 is a wasteful number, since it uses less digits than its factorization.

21329924 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3056 (or 3054 counting only the distinct ones).

The product of its digits is 7776, while the sum is 32.

The square root of 21329924 is about 4618.4330676107. The cubic root of 21329924 is about 277.3297345800.

The spelling of 21329924 in words is "twenty-one million, three hundred twenty-nine thousand, nine hundred twenty-four".