20711808 has 128 divisors (see below), whose sum is σ = 65973600. Its totient is φ = 6359040.

The previous prime is 20711807. The next prime is 20711833. The reversal of 20711808 is 80811702.

It is a tau number, because it is divible by the number of its divisors (128).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20711807) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 44698 + ... + 45158.

Almost surely, 2^20711808 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 20711808, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32986800).

20711808 is an abundant number, since it is smaller than the sum of its proper divisors (45261792).

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

20711808 is a wasteful number, since it uses less digits than its factorization.

20711808 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 497 (or 479 counting only the distinct ones).

The product of its (nonzero) digits is 896, while the sum is 27.

The square root of 20711808 is about 4551.0227421976. The cubic root of 20711808 is about 274.6245366410.

The spelling of 20711808 in words is "twenty million, seven hundred eleven thousand, eight hundred eight".