181981937 has 2 divisors, whose sum is σ = 181981938. Its totient is φ = 181981936.

The previous prime is 181981927. The next prime is 181981939. The reversal of 181981937 is 739189181.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 128165041 + 53816896 = 11321^2 + 7336^2 .

It is a cyclic number.

It is not a de Polignac number, because 181981937 - 2¹⁰ = 181980913 is a prime.

Together with 181981939, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 181981891 and 181981900.

It is not a weakly prime, because it can be changed into another prime (181981939) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 90990968 + 90990969.

It is an arithmetic number, because the mean of its divisors is an integer number (90990969).

Almost surely, 2^181981937 is an apocalyptic number.

It is an amenable number.

181981937 is a deficient number, since it is larger than the sum of its proper divisors (1).

181981937 is an equidigital number, since it uses as much as digits as its factorization.

181981937 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 108864, while the sum is 47.

The square root of 181981937 is about 13490.0680873004. The cubic root of 181981937 is about 566.6863622143.

The spelling of 181981937 in words is "one hundred eighty-one million, nine hundred eighty-one thousand, nine hundred thirty-seven".