21349 has 4 divisors (see below), whose sum is σ = 21964. Its totient is φ = 20736.

The previous prime is 21347. The next prime is 21377. The reversal of 21349 is 94312.

21349 is nontrivially palindromic in base 2.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 20449 + 900 = 143^2 + 30^2 .

It is a 4-Lehmer number, since φ(21349) divides (21349-1)⁴.

It is a cyclic number.

It is not a de Polignac number, because 21349 - 2¹ = 21347 is a prime.

It is a d-powerful number, because it can be written as 2¹¹ + 1 + 3⁷ + 4⁷ + 9³ .

It is a Duffinian number.

It is a plaindrome in base 14.

It is a nialpdrome in base 13.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21341) 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, 252 + ... + 325.

It is an arithmetic number, because the mean of its divisors is an integer number (5491).

2²¹³⁴⁹ is an apocalyptic number.

It is an amenable number.

21349 is a deficient number, since it is larger than the sum of its proper divisors (615).

21349 is an equidigital number, since it uses as much as digits as its factorization.

21349 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 614.

The product of its digits is 216, while the sum is 19.

The square root of 21349 is about 146.1129699924. The cubic root of 21349 is about 27.7412384753.

It can be divided in two parts, 213 and 49, that added together give a palindrome (262).

The spelling of 21349 in words is "twenty-one thousand, three hundred forty-nine".