20331 has 10 divisors (see below), whose sum is σ = 30492.
Its totient is φ = 13500.
The previous prime is 20327. The next prime is 20333. The reversal of 20331 is 13302.
It is a happy number.
It is not a de Polignac number, because 20331 - 22 = 20327 is a prime.
It is a super-2 number, since 2×203312 = 826699122, which contains 22 as substring.
It is a Harshad number since it is a multiple of its sum of digits (9).
It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 20331.
It is not an unprimeable number, because it can be changed into a prime (20333) by changing a digit.
It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 45 + ... + 206.
220331 is an apocalyptic number.
20331 is a deficient number, since it is larger than the sum of its proper divisors (10161).
20331 is an equidigital number, since it uses as much as digits as its factorization.
20331 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 263 (or 254 counting only the distinct ones).
The product of its (nonzero) digits is 18, while the sum is 9.
The square root of 20331 is about 142.5868156598.
The cubic root of 20331 is about 27.2931029552.
Adding to 20331 its reverse (13302), we get a palindrome (33633).
It can be divided in two parts, 20 and 331, that added together give a triangular number (351 = T26).
The spelling of 20331 in words is "twenty thousand, three hundred thirty-one".