20897568 has 144 divisors (see below), whose sum is σ = 65288160. Its totient is φ = 6500736.

The previous prime is 20897561. The next prime is 20897579. The reversal of 20897568 is 86579802.

20897568 is a `hidden beast` number, since 2 + 0 + 89 + 7 + 568 = 666.

It is a tau number, because it is divible by the number of its divisors (144).

It is not an unprimeable number, because it can be changed into a prime (20897561) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 311871 + ... + 311937.

It is an arithmetic number, because the mean of its divisors is an integer number (453390).

Almost surely, 2^20897568 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 20897568, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32644080).

20897568 is an abundant number, since it is smaller than the sum of its proper divisors (44390592).

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

20897568 is a wasteful number, since it uses less digits than its factorization.

20897568 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 124 (or 91 counting only the distinct ones).

The product of its (nonzero) digits is 241920, while the sum is 45.

The square root of 20897568 is about 4571.3857855141. The cubic root of 20897568 is about 275.4431115198.

The spelling of 20897568 in words is "twenty million, eight hundred ninety-seven thousand, five hundred sixty-eight".