21241 has 4 divisors (see below), whose sum is σ = 23184. Its totient is φ = 19300.

The previous prime is 21227. The next prime is 21247. The reversal of 21241 is 14212.

It is the 60-th star number.

21241 is an esthetic number in base 9, because in such base its adjacent digits differ by 1.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21241 - 2¹³ = 13049 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21247) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 955 + ... + 976.

It is an arithmetic number, because the mean of its divisors is an integer number (5796).

2²¹²⁴¹ is an apocalyptic number.

It is an amenable number.

21241 is a deficient number, since it is larger than the sum of its proper divisors (1943).

21241 is a wasteful number, since it uses less digits than its factorization.

21241 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1942.

The product of its digits is 16, while the sum is 10.

The square root of 21241 is about 145.7429243566. The cubic root of 21241 is about 27.6943803846.

Adding to 21241 its reverse (14212), we get a palindrome (35453).

It can be divided in two parts, 212 and 41, that added together give a triangular number (253 = T₂₂).

The spelling of 21241 in words is "twenty-one thousand, two hundred forty-one", and thus it is an iban number.