20798 has 4 divisors (see below), whose sum is σ = 31200. Its totient is φ = 10398.

The previous prime is 20789. The next prime is 20807. The reversal of 20798 is 89702.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 89702 = 2 ⋅44851.

It is an interprime number because it is at equal distance from previous prime (20789) and next prime (20807).

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5198 + ... + 5201.

It is an arithmetic number, because the mean of its divisors is an integer number (7800).

2²⁰⁷⁹⁸ is an apocalyptic number.

20798 is a deficient number, since it is larger than the sum of its proper divisors (10402).

20798 is a wasteful number, since it uses less digits than its factorization.

20798 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10401.

The product of its (nonzero) digits is 1008, while the sum is 26.

The square root of 20798 is about 144.2151170994. The cubic root of 20798 is about 27.5004958588.

It can be divided in two parts, 20 and 798, that added together give a palindrome (818).

The spelling of 20798 in words is "twenty thousand, seven hundred ninety-eight".