181890133 has 2 divisors, whose sum is σ = 181890134. Its totient is φ = 181890132.

The previous prime is 181890109. The next prime is 181890139. The reversal of 181890133 is 331098181.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 98843364 + 83046769 = 9942^2 + 9113^2 .

It is an emirp because it is prime and its reverse (331098181) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 181890133 - 2²¹ = 179792981 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (181890139) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 90945066 + 90945067.

It is an arithmetic number, because the mean of its divisors is an integer number (90945067).

Almost surely, 2^181890133 is an apocalyptic number.

It is an amenable number.

181890133 is a deficient number, since it is larger than the sum of its proper divisors (1).

181890133 is an equidigital number, since it uses as much as digits as its factorization.

181890133 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5184, while the sum is 34.

The square root of 181890133 is about 13486.6650065908. The cubic root of 181890133 is about 566.5910545403.

The spelling of 181890133 in words is "one hundred eighty-one million, eight hundred ninety thousand, one hundred thirty-three".