21141 has 14 divisors (see below), whose sum is σ = 32790. Its totient is φ = 13608.

The previous prime is 21139. The next prime is 21143. The reversal of 21141 is 14112.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21139) and next prime (21143).

It can be written as a sum of positive squares in only one way, i.e., 18225 + 2916 = 135^2 + 54^2 .

It is not a de Polignac number, because 21141 - 2¹ = 21139 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a Curzon number.

It is a nialpdrome in base 9.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21143) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 13 ways as a sum of consecutive naturals, for example, 715 + ... + 743.

2²¹¹⁴¹ is an apocalyptic number.

It is an amenable number.

21141 is a deficient number, since it is larger than the sum of its proper divisors (11649).

21141 is an frugal number, since it uses more digits than its factorization.

21141 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47 (or 32 counting only the distinct ones).

The product of its digits is 8, while the sum is 9.

The square root of 21141 is about 145.3994497926. The cubic root of 21141 is about 27.6508514312.

Adding to 21141 its reverse (14112), we get a palindrome (35253).

It can be divided in two parts, 211 and 41, that added together give a palindrome (252).

The spelling of 21141 in words is "twenty-one thousand, one hundred forty-one", and thus it is an iban number.