133565 has 4 divisors (see below), whose sum is σ = 160284. Its totient is φ = 106848.

The previous prime is 133559. The next prime is 133571. The reversal of 133565 is 565331.

Added to its reverse (565331) it gives a square (698896 = 836²).

133565 = 210² + 211² + 212².

133565 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 565331 = 13 ⋅43487.

It is an interprime number because it is at equal distance from previous prime (133559) and next prime (133571).

It can be written as a sum of positive squares in 2 ways, for example, as 98596 + 34969 = 314^2 + 187^2 .

It is a cyclic number.

It is not a de Polignac number, because 133565 - 2¹⁰ = 132541 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 133565.

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, 13352 + ... + 13361.

It is an arithmetic number, because the mean of its divisors is an integer number (40071).

2¹³³⁵⁶⁵ is an apocalyptic number.

It is an amenable number.

133565 is a deficient number, since it is larger than the sum of its proper divisors (26719).

133565 is an equidigital number, since it uses as much as digits as its factorization.

133565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26718.

The product of its digits is 1350, while the sum is 23.

The square root of 133565 is about 365.4654566440. The cubic root of 133565 is about 51.1168664316.

Adding to 133565 its reverse (565331), we get a palindrome (698896).

The spelling of 133565 in words is "one hundred thirty-three thousand, five hundred sixty-five".