20497 has 4 divisors (see below), whose sum is σ = 20800. Its totient is φ = 20196.

The previous prime is 20483. The next prime is 20507. The reversal of 20497 is 79402.

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 a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 20497 - 2⁷ = 20369 is a prime.

It is a Duffinian number.

It is a plaindrome in base 11.

It is a nialpdrome in base 12.

It is not an unprimeable number, because it can be changed into a prime (20407) 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, 4 + ... + 202.

It is an arithmetic number, because the mean of its divisors is an integer number (5200).

2²⁰⁴⁹⁷ is an apocalyptic number.

It is an amenable number.

20497 is a deficient number, since it is larger than the sum of its proper divisors (303).

20497 is a wasteful number, since it uses less digits than its factorization.

20497 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 302.

The product of its (nonzero) digits is 504, while the sum is 22.

The square root of 20497 is about 143.1677337950. The cubic root of 20497 is about 27.3671832592.

Adding to 20497 its reverse (79402), we get a palindrome (99899).

The spelling of 20497 in words is "twenty thousand, four hundred ninety-seven".