6561985481569 has 8 divisors (see below), whose sum is σ = 7589766340800. Its totient is φ = 5556793212816.

The previous prime is 6561985481549. The next prime is 6561985481599. The reversal of 6561985481569 is 9651845891656.

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 6561985481569 - 2²⁹ = 6561448610657 is a prime.

It is a super-4 number, since 4×6561985481569⁴ (a number of 52 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is not an unprimeable number, because it can be changed into a prime (6561985481549) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5647146994 + ... + 5647148155.

It is an arithmetic number, because the mean of its divisors is an integer number (948720792600).

Almost surely, 2^{6561985481569} is an apocalyptic number.

It is an amenable number.

6561985481569 is a deficient number, since it is larger than the sum of its proper divisors (1027780859231).

6561985481569 is a wasteful number, since it uses less digits than its factorization.

6561985481569 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11294295239.

The product of its digits is 559872000, while the sum is 73.

The spelling of 6561985481569 in words is "six trillion, five hundred sixty-one billion, nine hundred eighty-five million, four hundred eighty-one thousand, five hundred sixty-nine".