20437 has 4 divisors (see below), whose sum is σ = 20736. Its totient is φ = 20140.

The previous prime is 20431. The next prime is 20441. The reversal of 20437 is 73402.

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 a de Polignac number, because none of the positive numbers 2^k-20437 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20437.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 20437.

It is not an unprimeable number, because it can be changed into a prime (20431) 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, 12 + ... + 202.

It is an arithmetic number, because the mean of its divisors is an integer number (5184).

2²⁰⁴³⁷ is an apocalyptic number.

It is an amenable number.

20437 is a deficient number, since it is larger than the sum of its proper divisors (299).

20437 is a wasteful number, since it uses less digits than its factorization.

20437 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 298.

The product of its (nonzero) digits is 168, while the sum is 16.

The square root of 20437 is about 142.9580358007. The cubic root of 20437 is about 27.3404535618.

Adding to 20437 its reverse (73402), we get a palindrome (93839).

The spelling of 20437 in words is "twenty thousand, four hundred thirty-seven".