21834720 has 144 divisors (see below), whose sum is σ = 76068720. Its totient is φ = 5701632.

The previous prime is 21834719. The next prime is 21834737. The reversal of 21834720 is 2743812.

It is a tau number, because it is divible by the number of its divisors (144).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 84832 + ... + 85088.

It is an arithmetic number, because the mean of its divisors is an integer number (528255).

Almost surely, 2^21834720 is an apocalyptic number.

21834720 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 21834720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38034360).

21834720 is an abundant number, since it is smaller than the sum of its proper divisors (54234000).

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

21834720 is a wasteful number, since it uses less digits than its factorization.

21834720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 337 (or 326 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 27.

The square root of 21834720 is about 4672.7636362221. The cubic root of 21834720 is about 279.5004698944.

It can be divided in two parts, 2183 and 4720, that added together give a triangular number (6903 = T₁₁₇).

The spelling of 21834720 in words is "twenty-one million, eight hundred thirty-four thousand, seven hundred twenty".