20564646228 has 192 divisors, whose sum is σ = 64070899200. Its totient is φ = 5579642880.

The previous prime is 20564646209. The next prime is 20564646253. The reversal of 20564646228 is 82264646502.

20564646228 is a `hidden beast` number, since 2 + 0 + 564 + 6 + 4 + 62 + 28 = 666.

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 63 ways as a sum of consecutive naturals, for example, 1329676 + ... + 1345052.

It is an arithmetic number, because the mean of its divisors is an integer number (333702600).

Almost surely, 2^20564646228 is an apocalyptic number.

20564646228 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 20564646228, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32035449600).

20564646228 is an abundant number, since it is smaller than the sum of its proper divisors (43506252972).

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

20564646228 is a wasteful number, since it uses less digits than its factorization.

20564646228 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15487 (or 15479 counting only the distinct ones).

The product of its (nonzero) digits is 1105920, while the sum is 45.

The spelling of 20564646228 in words is "twenty billion, five hundred sixty-four million, six hundred forty-six thousand, two hundred twenty-eight".