133691 has 2 divisors, whose sum is σ = 133692. Its totient is φ = 133690.

The previous prime is 133673. The next prime is 133697. The reversal of 133691 is 196331.

It is a strong prime.

It is an emirp because it is prime and its reverse (196331) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 133691 - 2¹⁰ = 132667 is a prime.

It is a plaindrome in base 9.

It is not a weakly prime, because it can be changed into another prime (133697) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 66845 + 66846.

It is an arithmetic number, because the mean of its divisors is an integer number (66846).

2¹³³⁶⁹¹ is an apocalyptic number.

133691 is a deficient number, since it is larger than the sum of its proper divisors (1).

133691 is an equidigital number, since it uses as much as digits as its factorization.

133691 is an evil number, because the sum of its binary digits is even.

The product of its digits is 486, while the sum is 23.

The square root of 133691 is about 365.6377989213. The cubic root of 133691 is about 51.1329352644.

The spelling of 133691 in words is "one hundred thirty-three thousand, six hundred ninety-one".