20649820566 has 8 divisors (see below), whose sum is σ = 41299641144. Its totient is φ = 6883273520.

The previous prime is 20649820561. The next prime is 20649820567. The reversal of 20649820566 is 66502894602.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

20649820566 is an admirable number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20649820561) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 1720818375 + ... + 1720818386.

It is an arithmetic number, because the mean of its divisors is an integer number (5162455143).

Almost surely, 2^20649820566 is an apocalyptic number.

20649820566 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

20649820566 is a wasteful number, since it uses less digits than its factorization.

20649820566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3441636766.

The product of its (nonzero) digits is 1244160, while the sum is 48.

The spelling of 20649820566 in words is "twenty billion, six hundred forty-nine million, eight hundred twenty thousand, five hundred sixty-six".