31021 has 4 divisors (see below), whose sum is σ = 31552.
Its totient is φ = 30492.
The previous prime is 31019. The next prime is 31033. The reversal of 31021 is 12013.
31021 is nontrivially palindromic in base 12.
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, and also an emirpimes, since its reverse is a distinct semiprime: 12013 = 41 ⋅293.
It is a cyclic number.
It is not a de Polignac number, because 31021 - 21 = 31019 is a prime.
It is a Duffinian number.
31021 is a lucky number.
It is a junction number, because it is equal to n+sod(n) for n = 30995 and 31013.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (31051) 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, 165 + ... + 298.
It is an arithmetic number, because the mean of its divisors is an integer number (7888).
231021 is an apocalyptic number.
It is an amenable number.
31021 is a deficient number, since it is larger than the sum of its proper divisors (531).
31021 is an equidigital number, since it uses as much as digits as its factorization.
31021 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 530.
The product of its (nonzero) digits is 6, while the sum is 7.
The square root of 31021 is about 176.1277945130.
The cubic root of 31021 is about 31.4208983630.
Adding to 31021 its reverse (12013), we get a palindrome (43034).
It can be divided in two parts, 3 and 1021, that added together give a 10-th power (1024 = 210).
The spelling of 31021 in words is "thirty-one thousand, twenty-one".