20131808 has 48 divisors (see below), whose sum is σ = 43817760. Its totient is φ = 9056256.

The previous prime is 20131801. The next prime is 20131817. The reversal of 20131808 is 80813102.

It is a Harshad number since it is a multiple of its sum of digits (23).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20131801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11708 + ... + 13316.

It is an arithmetic number, because the mean of its divisors is an integer number (912870).

Almost surely, 2^20131808 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 20131808, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21908880).

20131808 is an abundant number, since it is smaller than the sum of its proper divisors (23685952).

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

20131808 is a wasteful number, since it uses less digits than its factorization.

20131808 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1659 (or 1651 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 23.

The square root of 20131808 is about 4486.8483370847. The cubic root of 20131808 is about 272.0367597377.

The spelling of 20131808 in words is "twenty million, one hundred thirty-one thousand, eight hundred eight".