181320613 has 2 divisors, whose sum is σ = 181320614. Its totient is φ = 181320612.

The previous prime is 181320593. The next prime is 181320653. The reversal of 181320613 is 316023181.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 160224964 + 21095649 = 12658^2 + 4593^2 .

It is a cyclic number.

It is not a de Polignac number, because 181320613 - 2²¹ = 179223461 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (181320653) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 90660306 + 90660307.

It is an arithmetic number, because the mean of its divisors is an integer number (90660307).

Almost surely, 2^181320613 is an apocalyptic number.

It is an amenable number.

181320613 is a deficient number, since it is larger than the sum of its proper divisors (1).

181320613 is an equidigital number, since it uses as much as digits as its factorization.

181320613 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 864, while the sum is 25.

The square root of 181320613 is about 13465.5342634446. The cubic root of 181320613 is about 565.9990812290. Note that the first 3 decimals are identical.

Adding to 181320613 its reverse (316023181), we get a palindrome (497343794).

The spelling of 181320613 in words is "one hundred eighty-one million, three hundred twenty thousand, six hundred thirteen".