20865545568 has 240 divisors, whose sum is σ = 72029178144. Its totient is φ = 5800273920.

The previous prime is 20865545537. The next prime is 20865545599. The reversal of 20865545568 is 86554556802.

It is a happy number.

20865545568 is a `hidden beast` number, since 2 + 0 + 86 + 5 + 5 + 4 + 556 + 8 = 666.

It is an interprime number because it is at equal distance from previous prime (20865545537) and next prime (20865545599).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 655788 + ... + 686868.

Almost surely, 2^20865545568 is an apocalyptic number.

20865545568 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20865545568, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36014589072).

20865545568 is an abundant number, since it is smaller than the sum of its proper divisors (51163632576).

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

20865545568 is a wasteful number, since it uses less digits than its factorization.

20865545568 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31147 (or 31130 counting only the distinct ones).

The product of its (nonzero) digits is 11520000, while the sum is 54.

The spelling of 20865545568 in words is "twenty billion, eight hundred sixty-five million, five hundred forty-five thousand, five hundred sixty-eight".