20878 has 16 divisors (see below), whose sum is σ = 37296. Its totient is φ = 8640.

The previous prime is 20873. The next prime is 20879. The reversal of 20878 is 87802.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20873) by changing a digit.

20878 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

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 7 ways as a sum of consecutive naturals, for example, 250 + ... + 322.

It is an arithmetic number, because the mean of its divisors is an integer number (2331).

2²⁰⁸⁷⁸ is an apocalyptic number.

20878 is a deficient number, since it is larger than the sum of its proper divisors (16418).

20878 is a wasteful number, since it uses less digits than its factorization.

20878 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99.

The product of its (nonzero) digits is 896, while the sum is 25.

The square root of 20878 is about 144.4922143231. The cubic root of 20878 is about 27.5357111816.

It can be divided in two parts, 20 and 878, that added together give a palindrome (898).

The spelling of 20878 in words is "twenty thousand, eight hundred seventy-eight".