20388816 has 120 divisors (see below), whose sum is σ = 66156480. Its totient is φ = 5741568.

The previous prime is 20388811. The next prime is 20388817. The reversal of 20388816 is 61888302.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20388811) 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 23 ways as a sum of consecutive naturals, for example, 113815 + ... + 113993.

It is an arithmetic number, because the mean of its divisors is an integer number (551304).

Almost surely, 2^20388816 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 20388816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33078240).

20388816 is an abundant number, since it is smaller than the sum of its proper divisors (45767664).

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

20388816 is a wasteful number, since it uses less digits than its factorization.

20388816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 313 (or 304 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 36.

The square root of 20388816 is about 4515.3976569069. The cubic root of 20388816 is about 273.1894993131.

The spelling of 20388816 in words is "twenty million, three hundred eighty-eight thousand, eight hundred sixteen".