21281241 has 8 divisors (see below), whose sum is σ = 28856160. Its totient is φ = 13946912.

The previous prime is 21281237. The next prime is 21281243. The reversal of 21281241 is 14218212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21281241 - 2² = 21281237 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21281243) 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 7 ways as a sum of consecutive naturals, for example, 59940 + ... + 60293.

It is an arithmetic number, because the mean of its divisors is an integer number (3607020).

Almost surely, 2^21281241 is an apocalyptic number.

It is an amenable number.

21281241 is a deficient number, since it is larger than the sum of its proper divisors (7574919).

21281241 is a wasteful number, since it uses less digits than its factorization.

21281241 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 120295.

The product of its digits is 256, while the sum is 21.

The square root of 21281241 is about 4613.1595463413. The cubic root of 21281241 is about 277.1185832077.

Adding to 21281241 its reverse (14218212), we get a palindrome (35499453).

The spelling of 21281241 in words is "twenty-one million, two hundred eighty-one thousand, two hundred forty-one".