133921 has 4 divisors (see below), whose sum is σ = 134932. Its totient is φ = 132912.

The previous prime is 133919. The next prime is 133949. The reversal of 133921 is 129331.

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, and also an emirpimes, since its reverse is a distinct semiprime: 129331 = 283 ⋅457.

It can be written as a sum of positive squares in 2 ways, for example, as 21025 + 112896 = 145^2 + 336^2 .

It is a cyclic number.

It is not a de Polignac number, because 133921 - 2¹ = 133919 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (133981) 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, 270 + ... + 583.

It is an arithmetic number, because the mean of its divisors is an integer number (33733).

2¹³³⁹²¹ is an apocalyptic number.

It is an amenable number.

133921 is a deficient number, since it is larger than the sum of its proper divisors (1011).

133921 is an equidigital number, since it uses as much as digits as its factorization.

133921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1010.

The product of its digits is 162, while the sum is 19.

The square root of 133921 is about 365.9521826687. The cubic root of 133921 is about 51.1622412443.

The spelling of 133921 in words is "one hundred thirty-three thousand, nine hundred twenty-one".