671381993 has 2 divisors, whose sum is σ = 671381994. Its totient is φ = 671381992.

The previous prime is 671381957. The next prime is 671382013. The reversal of 671381993 is 399183176.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 391723264 + 279658729 = 19792^2 + 16723^2 .

It is a cyclic number.

It is not a de Polignac number, because 671381993 - 2¹² = 671377897 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (671381393) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 335690996 + 335690997.

It is an arithmetic number, because the mean of its divisors is an integer number (335690997).

Almost surely, 2^671381993 is an apocalyptic number.

It is an amenable number.

671381993 is a deficient number, since it is larger than the sum of its proper divisors (1).

671381993 is an equidigital number, since it uses as much as digits as its factorization.

671381993 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 244944, while the sum is 47.

The square root of 671381993 is about 25911.0399829879. The cubic root of 671381993 is about 875.6352363494.

The spelling of 671381993 in words is "six hundred seventy-one million, three hundred eighty-one thousand, nine hundred ninety-three".