21310 has 8 divisors (see below), whose sum is σ = 38376. Its totient is φ = 8520.

The previous prime is 21283. The next prime is 21313. The reversal of 21310 is 1312.

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

It is a super-2 number, since 2×21310² = 908232200, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21293 and 21302.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21313) 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, 1056 + ... + 1075.

It is an arithmetic number, because the mean of its divisors is an integer number (4797).

2²¹³¹⁰ is an apocalyptic number.

21310 is a deficient number, since it is larger than the sum of its proper divisors (17066).

21310 is a wasteful number, since it uses less digits than its factorization.

21310 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2138.

The product of its (nonzero) digits is 6, while the sum is 7.

The square root of 21310 is about 145.9794506086. The cubic root of 21310 is about 27.7243357667.

Adding to 21310 its reverse (1312), we get a palindrome (22622).

The spelling of 21310 in words is "twenty-one thousand, three hundred ten", and thus it is an iban number.