20478 has 8 divisors (see below), whose sum is σ = 40968. Its totient is φ = 6824.

The previous prime is 20477. The next prime is 20479. The reversal of 20478 is 87402.

Added to its reverse (87402) it gives a triangular number (107880 = T₄₆₄).

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (20477) and next prime (20479).

It is a sphenic number, since it is the product of 3 distinct primes.

20478 is an admirable number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20477) 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, 1701 + ... + 1712.

It is an arithmetic number, because the mean of its divisors is an integer number (5121).

2²⁰⁴⁷⁸ is an apocalyptic number.

20478 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (20484).

20478 is a wasteful number, since it uses less digits than its factorization.

20478 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3418.

The product of its (nonzero) digits is 448, while the sum is 21.

The square root of 20478 is about 143.1013626770. The cubic root of 20478 is about 27.3587245054.

Adding to 20478 its reverse (87402), we get a triangular number (107880 = T₄₆₄).

It can be divided in two parts, 204 and 78, that added together give a palindrome (282).

The spelling of 20478 in words is "twenty thousand, four hundred seventy-eight".