181226813 has 2 divisors, whose sum is σ = 181226814. Its totient is φ = 181226812.

The previous prime is 181226797. The next prime is 181226831. The reversal of 181226813 is 318622181.

Together with next prime (181226831) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 181225444 + 1369 = 13462^2 + 37^2 .

It is a cyclic number.

It is not a de Polignac number, because 181226813 - 2⁴ = 181226797 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 181226813.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (181226833) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 90613406 + 90613407.

It is an arithmetic number, because the mean of its divisors is an integer number (90613407).

Almost surely, 2^181226813 is an apocalyptic number.

It is an amenable number.

181226813 is a deficient number, since it is larger than the sum of its proper divisors (1).

181226813 is an equidigital number, since it uses as much as digits as its factorization.

181226813 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4608, while the sum is 32.

The square root of 181226813 is about 13462.0508467321. The cubic root of 181226813 is about 565.9014643236.

Adding to 181226813 its reverse (318622181), we get a palindrome (499848994).

The spelling of 181226813 in words is "one hundred eighty-one million, two hundred twenty-six thousand, eight hundred thirteen".