20565548640 has 288 divisors, whose sum is σ = 86375854656. Its totient is φ = 4339077120.

The previous prime is 20565548551. The next prime is 20565548687. The reversal of 20565548640 is 4684556502.

20565548640 is a `hidden beast` number, since 2 + 0 + 5 + 65 + 548 + 6 + 40 = 666.

It is a tau number, because it is divible by the number of its divisors (288).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 52570 + ... + 209510.

It is an arithmetic number, because the mean of its divisors is an integer number (299916162).

Almost surely, 2^20565548640 is an apocalyptic number.

20565548640 is a gapful number since it is divisible by the number (20) 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 20565548640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43187927328).

20565548640 is an abundant number, since it is smaller than the sum of its proper divisors (65810306016).

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

20565548640 is a wasteful number, since it uses less digits than its factorization.

20565548640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 156982 (or 156971 counting only the distinct ones).

The product of its (nonzero) digits is 1152000, while the sum is 45.

The spelling of 20565548640 in words is "twenty billion, five hundred sixty-five million, five hundred forty-eight thousand, six hundred forty".