133813 has 2 divisors, whose sum is σ = 133814.
Its totient is φ = 133812.
The previous prime is 133811. The next prime is 133831. The reversal of 133813 is 318331.
Together with next prime (133831) it forms an Ormiston pair, because they use the same digits, order apart.
It is a weak prime.
It can be written as a sum of positive squares in only one way, i.e., 79524 + 54289 = 282^2 + 233^2
It is a cyclic number.
It is not a de Polignac number, because 133813 - 21 = 133811 is a prime.
Together with 133811, it forms a pair of twin primes.
It is a plaindrome in base 15.
It is a nialpdrome in base 12.
It is a congruent number.
It is not a weakly prime, because it can be changed into another prime (133811) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 66906 + 66907.
It is an arithmetic number, because the mean of its divisors is an integer number (66907).
2133813 is an apocalyptic number.
It is an amenable number.
133813 is a deficient number, since it is larger than the sum of its proper divisors (1).
133813 is an equidigital number, since it uses as much as digits as its factorization.
133813 is an evil number, because the sum of its binary digits is even.
The product of its digits is 216, while the sum is 19.
The square root of 133813 is about 365.8045926448.
The cubic root of 133813 is about 51.1484843577.
It can be divided in two parts, 133 and 813, that added together give a triangular number (946 = T43).
The spelling of 133813 in words is "one hundred thirty-three thousand, eight hundred thirteen".