181351861 has 2 divisors, whose sum is σ = 181351862. Its totient is φ = 181351860.

The previous prime is 181351843. The next prime is 181351867. The reversal of 181351861 is 168153181.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 178222500 + 3129361 = 13350^2 + 1769^2 .

It is a cyclic number.

It is not a de Polignac number, because 181351861 - 2⁹ = 181351349 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (181351867) 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, 90675930 + 90675931.

It is an arithmetic number, because the mean of its divisors is an integer number (90675931).

Almost surely, 2^181351861 is an apocalyptic number.

It is an amenable number.

181351861 is a deficient number, since it is larger than the sum of its proper divisors (1).

181351861 is an equidigital number, since it uses as much as digits as its factorization.

181351861 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5760, while the sum is 34.

The square root of 181351861 is about 13466.6945090471. The cubic root of 181351861 is about 566.0315932953.

The spelling of 181351861 in words is "one hundred eighty-one million, three hundred fifty-one thousand, eight hundred sixty-one".