181312133 has 4 divisors (see below), whose sum is σ = 184385280. Its totient is φ = 178238988.

The previous prime is 181312129. The next prime is 181312139. The reversal of 181312133 is 331213181.

181312133 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 181312133 - 2² = 181312129 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 181312099 and 181312108.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (181312139) 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, 1536485 + ... + 1536602.

It is an arithmetic number, because the mean of its divisors is an integer number (46096320).

Almost surely, 2^181312133 is an apocalyptic number.

It is an amenable number.

181312133 is a deficient number, since it is larger than the sum of its proper divisors (3073147).

181312133 is an equidigital number, since it uses as much as digits as its factorization.

181312133 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3073146.

The product of its digits is 432, while the sum is 23.

The square root of 181312133 is about 13465.2193817999. The cubic root of 181312133 is about 565.9902575456.

The spelling of 181312133 in words is "one hundred eighty-one million, three hundred twelve thousand, one hundred thirty-three".