20808284 has 48 divisors (see below), whose sum is σ = 44083200. Its totient is φ = 8401536.

The previous prime is 20808251. The next prime is 20808301. The reversal of 20808284 is 48280802.

It is a self number, because there is not a number n which added to its sum of digits gives 20808284.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 50672 + ... + 51080.

It is an arithmetic number, because the mean of its divisors is an integer number (918400).

Almost surely, 2^20808284 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20808284, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22041600).

20808284 is an abundant number, since it is smaller than the sum of its proper divisors (23274916).

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

20808284 is a wasteful number, since it uses less digits than its factorization.

20808284 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 522 (or 520 counting only the distinct ones).

The product of its (nonzero) digits is 8192, while the sum is 32.

The square root of 20808284 is about 4561.6098035672. The cubic root of 20808284 is about 275.0502784103.

The spelling of 20808284 in words is "twenty million, eight hundred eight thousand, two hundred eighty-four".