13021 has 4 divisors (see below), whose sum is σ = 13500.
Its totient is φ = 12544.
The previous prime is 13009. The next prime is 13033. The reversal of 13021 is 12031.
It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12031 = 53 ⋅227.
It is an interprime number because it is at equal distance from previous prime (13009) and next prime (13033).
It can be written as a sum of positive squares in 2 ways, for example, as 7396 + 5625 = 86^2 + 75^2
It is a 4-Lehmer number, since φ(13021) divides (13021-1)4.
It is a cyclic number.
It is not a de Polignac number, because 13021 - 27 = 12893 is a prime.
It is a Duffinian number.
13021 is a lucky number.
It is a nialpdrome in base 12.
It is a junction number, because it is equal to n+sod(n) for n = 12995 and 13013.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (13001) 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, 196 + ... + 253.
It is an arithmetic number, because the mean of its divisors is an integer number (3375).
213021 is an apocalyptic number.
It is an amenable number.
13021 is a deficient number, since it is larger than the sum of its proper divisors (479).
13021 is an equidigital number, since it uses as much as digits as its factorization.
13021 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 478.
The product of its (nonzero) digits is 6, while the sum is 7.
The square root of 13021 is about 114.1095964413.
The cubic root of 13021 is about 23.5260010988.
Adding to 13021 its reverse (12031), we get a palindrome (25052).
Subtracting from 13021 its reverse (12031), we obtain a triangular number (990 = T44).
It can be divided in two parts, 130 and 21, that added together give a palindrome (151).
The spelling of 13021 in words is "thirteen thousand, twenty-one".