20783 has 4 divisors (see below), whose sum is σ = 23760. Its totient is φ = 17808.

The previous prime is 20773. The next prime is 20789. The reversal of 20783 is 38702.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 20783 - 2⁶ = 20719 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20789) 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, 1478 + ... + 1491.

It is an arithmetic number, because the mean of its divisors is an integer number (5940).

2²⁰⁷⁸³ is an apocalyptic number.

20783 is a deficient number, since it is larger than the sum of its proper divisors (2977).

20783 is an equidigital number, since it uses as much as digits as its factorization.

20783 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2976.

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

The square root of 20783 is about 144.1631020754. The cubic root of 20783 is about 27.4938829370.

The spelling of 20783 in words is "twenty thousand, seven hundred eighty-three".