13656511217 has 4 divisors (see below), whose sum is σ = 13661431716. Its totient is φ = 13651590720.

The previous prime is 13656511207. The next prime is 13656511223. The reversal of 13656511217 is 71211565631.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 71211565631 = 173 ⋅411627547.

It can be written as a sum of positive squares in 2 ways, for example, as 8131710976 + 5524800241 = 90176^2 + 74329^2 .

It is a cyclic number.

It is not a de Polignac number, because 13656511217 - 2¹² = 13656507121 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (13656511207) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2456084 + ... + 2461637.

It is an arithmetic number, because the mean of its divisors is an integer number (3415357929).

Almost surely, 2^13656511217 is an apocalyptic number.

It is an amenable number.

13656511217 is a deficient number, since it is larger than the sum of its proper divisors (4920499).

13656511217 is an equidigital number, since it uses as much as digits as its factorization.

13656511217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4920498.

The product of its digits is 37800, while the sum is 38.

The spelling of 13656511217 in words is "thirteen billion, six hundred fifty-six million, five hundred eleven thousand, two hundred seventeen".