20245 has 4 divisors (see below), whose sum is σ = 24300. Its totient is φ = 16192.

The previous prime is 20233. The next prime is 20249. The reversal of 20245 is 54202.

It is a happy number.

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 6084 + 14161 = 78^2 + 119^2 .

It is a cyclic number.

It is not a de Polignac number, because 20245 - 2⁷ = 20117 is a prime.

It is a nialpdrome in base 12 and base 14.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20249) 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, 2020 + ... + 2029.

It is an arithmetic number, because the mean of its divisors is an integer number (6075).

2²⁰²⁴⁵ is an apocalyptic number.

It is an amenable number.

20245 is a deficient number, since it is larger than the sum of its proper divisors (4055).

20245 is an equidigital number, since it uses as much as digits as its factorization.

20245 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4054.

The product of its (nonzero) digits is 80, while the sum is 13.

The square root of 20245 is about 142.2849254138. The cubic root of 20245 is about 27.2545653491.

Adding to 20245 its reverse (54202), we get a palindrome (74447).

It can be divided in two parts, 20 and 245, that multiplied together give a square (4900 = 70²).

The spelling of 20245 in words is "twenty thousand, two hundred forty-five".