20564647643245 has 8 divisors (see below), whose sum is σ = 26129199358584. Its totient is φ = 15483969990144.

The previous prime is 20564647643213. The next prime is 20564647643249. The reversal of 20564647643245 is 54234674646502.

It can be written as a sum of positive squares in 4 ways, for example, as 4334336756649 + 16230310886596 = 2081907^2 + 4028686^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 20564647643245 - 2⁵ = 20564647643213 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20564647643245.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20564647643249) 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 7 ways as a sum of consecutive naturals, for example, 120968515464 + ... + 120968515633.

It is an arithmetic number, because the mean of its divisors is an integer number (3266149919823).

Almost surely, 2^{20564647643245} is an apocalyptic number.

It is an amenable number.

20564647643245 is a deficient number, since it is larger than the sum of its proper divisors (5564551715339).

20564647643245 is a wasteful number, since it uses less digits than its factorization.

20564647643245 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 241937031119.

The product of its (nonzero) digits is 116121600, while the sum is 58.

The spelling of 20564647643245 in words is "twenty trillion, five hundred sixty-four billion, six hundred forty-seven million, six hundred forty-three thousand, two hundred forty-five".