20556547785 has 48 divisors (see below), whose sum is σ = 36201129744. Its totient is φ = 10788857856.

The previous prime is 20556547777. The next prime is 20556547789. The reversal of 20556547785 is 58774565502.

20556547785 is a `hidden beast` number, since 2 + 0 + 5 + 565 + 4 + 7 + 78 + 5 = 666.

It can be written as a sum of positive squares in 8 ways, for example, as 5489476281 + 15067071504 = 74091^2 + 122748^2 .

It is not a de Polignac number, because 20556547785 - 2³ = 20556547777 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20556547789) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1494399 + ... + 1508091.

It is an arithmetic number, because the mean of its divisors is an integer number (754190203).

Almost surely, 2^20556547785 is an apocalyptic number.

It is an amenable number.

20556547785 is a deficient number, since it is larger than the sum of its proper divisors (15644581959).

20556547785 is a wasteful number, since it uses less digits than its factorization.

20556547785 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14234 (or 14231 counting only the distinct ones).

The product of its (nonzero) digits is 11760000, while the sum is 54.

The spelling of 20556547785 in words is "twenty billion, five hundred fifty-six million, five hundred forty-seven thousand, seven hundred eighty-five".