20045 has 8 divisors (see below), whose sum is σ = 25440. Its totient is φ = 15120.

The previous prime is 20029. The next prime is 20047. The reversal of 20045 is 54002.

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

It is not a de Polignac number, because 20045 - 2⁴ = 20029 is a prime.

20045 is a modest number, since divided by 45 gives 20 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20047) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11 + ... + 200.

It is an arithmetic number, because the mean of its divisors is an integer number (3180).

2²⁰⁰⁴⁵ is an apocalyptic number.

It is an amenable number.

20045 is a deficient number, since it is larger than the sum of its proper divisors (5395).

20045 is a wasteful number, since it uses less digits than its factorization.

20045 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 235.

The product of its (nonzero) digits is 40, while the sum is 11.

The square root of 20045 is about 141.5803658704. The cubic root of 20045 is about 27.1645190485.

Adding to 20045 its reverse (54002), we get a palindrome (74047).

The spelling of 20045 in words is "twenty thousand, forty-five".