20811072 has 56 divisors (see below), whose sum is σ = 55632096. Its totient is φ = 6865408.

The previous prime is 20811041. The next prime is 20811079. The reversal of 20811072 is 27011802.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20811079) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20038 + ... + 21050.

Almost surely, 2^20811072 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 20811072, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27816048).

20811072 is an abundant number, since it is smaller than the sum of its proper divisors (34821024).

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

20811072 is a wasteful number, since it uses less digits than its factorization.

20811072 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1135 (or 1125 counting only the distinct ones).

The product of its (nonzero) digits is 224, while the sum is 21.

The square root of 20811072 is about 4561.9153872031. The cubic root of 20811072 is about 275.0625620747.

Adding to 20811072 its reverse (27011802), we get a palindrome (47822874).

The spelling of 20811072 in words is "twenty million, eight hundred eleven thousand, seventy-two".