20665560544 has 48 divisors (see below), whose sum is σ = 42106720320. Its totient is φ = 9972103680.

The previous prime is 20665560529. The next prime is 20665560589. The reversal of 20665560544 is 44506556602.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 20665560544.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3366502 + ... + 3372634.

It is an arithmetic number, because the mean of its divisors is an integer number (877223340).

Almost surely, 2^20665560544 is an apocalyptic number.

It is an amenable number.

20665560544 is an abundant number, since it is smaller than the sum of its proper divisors (21441159776).

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

20665560544 is a wasteful number, since it uses less digits than its factorization.

20665560544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9803 (or 9795 counting only the distinct ones).

The product of its (nonzero) digits is 864000, while the sum is 43.

The spelling of 20665560544 in words is "twenty billion, six hundred sixty-five million, five hundred sixty thousand, five hundred forty-four".