13661215105 has 4 divisors (see below), whose sum is σ = 16393458132. Its totient is φ = 10928972080.

The previous prime is 13661215081. The next prime is 13661215123. The reversal of 13661215105 is 50151216631.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 5301587344 + 8359627761 = 72812^2 + 91431^2 .

It is a de Polignac number, because none of the positive numbers 2^k-13661215105 is a prime.

It is a super-2 number, since 2×13661215105² (a number of 21 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1366121506 + ... + 1366121515.

It is an arithmetic number, because the mean of its divisors is an integer number (4098364533).

Almost surely, 2^13661215105 is an apocalyptic number.

It is an amenable number.

13661215105 is a deficient number, since it is larger than the sum of its proper divisors (2732243027).

13661215105 is an equidigital number, since it uses as much as digits as its factorization.

13661215105 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2732243026.

The product of its (nonzero) digits is 5400, while the sum is 31.

The spelling of 13661215105 in words is "thirteen billion, six hundred sixty-one million, two hundred fifteen thousand, one hundred five".