13615565 has 4 divisors (see below), whose sum is σ = 16338684. Its totient is φ = 10892448.

The previous prime is 13615559. The next prime is 13615573. The reversal of 13615565 is 56551631.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 56551631 = 347 ⋅162973.

It can be written as a sum of positive squares in 2 ways, for example, as 4116841 + 9498724 = 2029^2 + 3082^2 .

It is a cyclic number.

It is not a de Polignac number, because 13615565 - 2⁴ = 13615549 is a prime.

It is a super-2 number, since 2×13615565² = 370767220538450, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent 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, 1361552 + ... + 1361561.

It is an arithmetic number, because the mean of its divisors is an integer number (4084671).

Almost surely, 2^13615565 is an apocalyptic number.

It is an amenable number.

13615565 is a deficient number, since it is larger than the sum of its proper divisors (2723119).

13615565 is an equidigital number, since it uses as much as digits as its factorization.

13615565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2723118.

The product of its digits is 13500, while the sum is 32.

The square root of 13615565 is about 3689.9275060630. The cubic root of 13615565 is about 238.7876652654.

The spelling of 13615565 in words is "thirteen million, six hundred fifteen thousand, five hundred sixty-five".