21241340 has 48 divisors (see below), whose sum is σ = 47083680. Its totient is φ = 8037120.

The previous prime is 21241333. The next prime is 21241343. The reversal of 21241340 is 4314212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21241343) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 30395 + ... + 31085.

It is an arithmetic number, because the mean of its divisors is an integer number (980910).

Almost surely, 2^21241340 is an apocalyptic number.

21241340 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 21241340, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23541840).

21241340 is an abundant number, since it is smaller than the sum of its proper divisors (25842340).

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

21241340 is a wasteful number, since it uses less digits than its factorization.

21241340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 782 (or 780 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 17.

The square root of 21241340 is about 4608.8328240456. The cubic root of 21241340 is about 276.9452814975.

Adding to 21241340 its reverse (4314212), we get a palindrome (25555552).

The spelling of 21241340 in words is "twenty-one million, two hundred forty-one thousand, three hundred forty".