20837 has 4 divisors (see below), whose sum is σ = 21216. Its totient is φ = 20460.

The previous prime is 20809. The next prime is 20849. The reversal of 20837 is 73802.

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 an emirpimes, since its reverse is a distinct semiprime: 73802 = 2 ⋅36901.

It is a cyclic number.

It is not a de Polignac number, because 20837 - 2⁶ = 20773 is a prime.

It is a Duffinian number.

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 20837.

It is not an unprimeable number, because it can be changed into a prime (20807) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 89 + ... + 222.

It is an arithmetic number, because the mean of its divisors is an integer number (5304).

2²⁰⁸³⁷ is an apocalyptic number.

It is an amenable number.

20837 is a deficient number, since it is larger than the sum of its proper divisors (379).

20837 is an equidigital number, since it uses as much as digits as its factorization.

20837 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 378.

The product of its (nonzero) digits is 336, while the sum is 20.

The square root of 20837 is about 144.3502684445. The cubic root of 20837 is about 27.5176745883.

The spelling of 20837 in words is "twenty thousand, eight hundred thirty-seven".