21334240 has 48 divisors (see below), whose sum is σ = 51492672. Its totient is φ = 8349184.

The previous prime is 21334219. The next prime is 21334241. The reversal of 21334240 is 4243312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21334241) 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, 6102 + ... + 8938.

It is an arithmetic number, because the mean of its divisors is an integer number (1072764).

Almost surely, 2^21334240 is an apocalyptic number.

21334240 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 21334240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25746336).

21334240 is an abundant number, since it is smaller than the sum of its proper divisors (30158432).

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

21334240 is a wasteful number, since it uses less digits than its factorization.

21334240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2899 (or 2891 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 19.

The square root of 21334240 is about 4618.9003020200. The cubic root of 21334240 is about 277.3484387318.

Adding to 21334240 its reverse (4243312), we get a palindrome (25577552).

It can be divided in two parts, 213 and 34240, that added together give a triangular number (34453 = T₂₆₂).

The spelling of 21334240 in words is "twenty-one million, three hundred thirty-four thousand, two hundred forty".