13561221065 has 8 divisors (see below), whose sum is σ = 18598246080. Its totient is φ = 9299122992.

The previous prime is 13561221041. The next prime is 13561221073. The reversal of 13561221065 is 56012216531.

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 13561221065 - 2⁸ = 13561220809 is a prime.

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 7 ways as a sum of consecutive naturals, for example, 193731695 + ... + 193731764.

It is an arithmetic number, because the mean of its divisors is an integer number (2324780760).

Almost surely, 2^13561221065 is an apocalyptic number.

It is an amenable number.

13561221065 is a deficient number, since it is larger than the sum of its proper divisors (5037025015).

13561221065 is an equidigital number, since it uses as much as digits as its factorization.

13561221065 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 387463471.

The product of its (nonzero) digits is 10800, while the sum is 32.

Adding to 13561221065 its reverse (56012216531), we get a palindrome (69573437596).

The spelling of 13561221065 in words is "thirteen billion, five hundred sixty-one million, two hundred twenty-one thousand, sixty-five".