21829920 has 192 divisors, whose sum is σ = 80559360. Its totient is φ = 4866048.

The previous prime is 21829897. The next prime is 21829933. The reversal of 21829920 is 2992812.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 245236 + ... + 245324.

It is an arithmetic number, because the mean of its divisors is an integer number (419580).

Almost surely, 2^21829920 is an apocalyptic number.

21829920 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21829920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40279680).

21829920 is an abundant number, since it is smaller than the sum of its proper divisors (58729440).

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

21829920 is a wasteful number, since it uses less digits than its factorization.

21829920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 187 (or 179 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 33.

The square root of 21829920 is about 4672.2499933116. The cubic root of 21829920 is about 279.4799872171.

The spelling of 21829920 in words is "twenty-one million, eight hundred twenty-nine thousand, nine hundred twenty".