181938313 has 2 divisors, whose sum is σ = 181938314. Its totient is φ = 181938312.

The previous prime is 181938307. The next prime is 181938377. The reversal of 181938313 is 313839181.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 174583369 + 7354944 = 13213^2 + 2712^2 .

It is an emirp because it is prime and its reverse (313839181) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 181938313 - 2⁹ = 181937801 is a prime.

It is not a weakly prime, because it can be changed into another prime (181938013) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 90969156 + 90969157.

It is an arithmetic number, because the mean of its divisors is an integer number (90969157).

Almost surely, 2^181938313 is an apocalyptic number.

It is an amenable number.

181938313 is a deficient number, since it is larger than the sum of its proper divisors (1).

181938313 is an equidigital number, since it uses as much as digits as its factorization.

181938313 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 15552, while the sum is 37.

The square root of 181938313 is about 13488.4510971423. The cubic root of 181938313 is about 566.6410773143.

The spelling of 181938313 in words is "one hundred eighty-one million, nine hundred thirty-eight thousand, three hundred thirteen".