133891 has 4 divisors (see below), whose sum is σ = 134784. Its totient is φ = 133000.

The previous prime is 133877. The next prime is 133919. The reversal of 133891 is 198331.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 133891 - 2⁹ = 133379 is a prime.

It is a Duffinian number.

133891 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (133801) 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, 160 + ... + 541.

It is an arithmetic number, because the mean of its divisors is an integer number (33696).

2¹³³⁸⁹¹ is an apocalyptic number.

133891 is a deficient number, since it is larger than the sum of its proper divisors (893).

133891 is an equidigital number, since it uses as much as digits as its factorization.

133891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 892.

The product of its digits is 648, while the sum is 25.

The square root of 133891 is about 365.9111914112. The cubic root of 133891 is about 51.1584206290.

It can be divided in two parts, 133 and 891, that added together give a 10-th power (1024 = 2¹⁰).

The spelling of 133891 in words is "one hundred thirty-three thousand, eight hundred ninety-one".