181213133 has 4 divisors (see below), whose sum is σ = 181362528. Its totient is φ = 181063740.

The previous prime is 181213117. The next prime is 181213139. The reversal of 181213133 is 331312181.

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 181213133 - 2⁴ = 181213117 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 181213099 and 181213108.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (181213139) 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, 72863 + ... + 75308.

It is an arithmetic number, because the mean of its divisors is an integer number (45340632).

Almost surely, 2^181213133 is an apocalyptic number.

It is an amenable number.

181213133 is a deficient number, since it is larger than the sum of its proper divisors (149395).

181213133 is a wasteful number, since it uses less digits than its factorization.

181213133 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 149394.

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

The square root of 181213133 is about 13461.5427421971. The cubic root of 181213133 is about 565.8872248435.

The spelling of 181213133 in words is "one hundred eighty-one million, two hundred thirteen thousand, one hundred thirty-three".