13566550561 has 4 divisors (see below), whose sum is σ = 13568065792. Its totient is φ = 13565035332.

The previous prime is 13566550559. The next prime is 13566550589. The reversal of 13566550561 is 16505566531.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 16505566531 = 18859 ⋅875209.

It is a cyclic number.

It is not a de Polignac number, because 13566550561 - 2¹ = 13566550559 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (13566550061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 744105 + ... + 762118.

It is an arithmetic number, because the mean of its divisors is an integer number (3392016448).

Almost surely, 2^13566550561 is an apocalyptic number.

It is an amenable number.

13566550561 is a deficient number, since it is larger than the sum of its proper divisors (1515231).

13566550561 is an equidigital number, since it uses as much as digits as its factorization.

13566550561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1515230.

The product of its (nonzero) digits is 405000, while the sum is 43.

The spelling of 13566550561 in words is "thirteen billion, five hundred sixty-six million, five hundred fifty thousand, five hundred sixty-one".