133971 has 4 divisors (see below), whose sum is σ = 178632. Its totient is φ = 89312.

The previous prime is 133967. The next prime is 133979. The reversal of 133971 is 179331.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 133971 - 2² = 133967 is a prime.

It is a D-number.

It is not an unprimeable number, because it can be changed into a prime (133979) 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, 22326 + ... + 22331.

It is an arithmetic number, because the mean of its divisors is an integer number (44658).

2¹³³⁹⁷¹ is an apocalyptic number.

133971 is a deficient number, since it is larger than the sum of its proper divisors (44661).

133971 is an equidigital number, since it uses as much as digits as its factorization.

133971 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44660.

The product of its digits is 567, while the sum is 24.

The square root of 133971 is about 366.0204912297. The cubic root of 133971 is about 51.1686076687.

The spelling of 133971 in words is "one hundred thirty-three thousand, nine hundred seventy-one".