20447 has 8 divisors (see below), whose sum is σ = 24576. Its totient is φ = 16632.

The previous prime is 20443. The next prime is 20477. The reversal of 20447 is 74402.

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

It is not a de Polignac number, because 20447 - 2² = 20443 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20441) 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, 98 + ... + 224.

It is an arithmetic number, because the mean of its divisors is an integer number (3072).

2²⁰⁴⁴⁷ is an apocalyptic number.

20447 is a deficient number, since it is larger than the sum of its proper divisors (4129).

20447 is a wasteful number, since it uses less digits than its factorization.

20447 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 157.

The product of its (nonzero) digits is 224, while the sum is 17.

The square root of 20447 is about 142.9930068220. The cubic root of 20447 is about 27.3449121411.

Adding to 20447 its reverse (74402), we get a palindrome (94849).

The spelling of 20447 in words is "twenty thousand, four hundred forty-seven", and thus it is an iban number.