20945861568 has 168 divisors, whose sum is σ = 64201578480. Its totient is φ = 6505881600.

The previous prime is 20945861561. The next prime is 20945861609. The reversal of 20945861568 is 86516854902.

20945861568 is a `hidden beast` number, since 2 + 0 + 9 + 4 + 586 + 1 + 56 + 8 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20945861561) 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, 978403 + ... + 999581.

Almost surely, 2^20945861568 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 20945861568, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32100789240).

20945861568 is an abundant number, since it is smaller than the sum of its proper divisors (43255716912).

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

20945861568 is a wasteful number, since it uses less digits than its factorization.

20945861568 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21315 (or 21302 counting only the distinct ones).

The product of its (nonzero) digits is 4147200, while the sum is 54.

The spelling of 20945861568 in words is "twenty billion, nine hundred forty-five million, eight hundred sixty-one thousand, five hundred sixty-eight".