133831811 has 4 divisors (see below), whose sum is σ = 133862352. Its totient is φ = 133801272.

The previous prime is 133831807. The next prime is 133831813. The reversal of 133831811 is 118138331.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 118138331 = 5081 ⋅23251.

It is a cyclic number.

It is not a de Polignac number, because 133831811 - 2² = 133831807 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (133831813) 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, 7316 + ... + 17921.

It is an arithmetic number, because the mean of its divisors is an integer number (33465588).

Almost surely, 2^133831811 is an apocalyptic number.

133831811 is a deficient number, since it is larger than the sum of its proper divisors (30541).

133831811 is an equidigital number, since it uses as much as digits as its factorization.

133831811 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30540.

The product of its digits is 1728, while the sum is 29.

The square root of 133831811 is about 11568.5699634830. The cubic root of 133831811 is about 511.5088100835.

The spelling of 133831811 in words is "one hundred thirty-three million, eight hundred thirty-one thousand, eight hundred eleven".