681727187 has 2 divisors, whose sum is σ = 681727188. Its totient is φ = 681727186.

The previous prime is 681727159. The next prime is 681727229. The reversal of 681727187 is 781727186.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 681727187 - 2⁸ = 681726931 is a prime.

It is not a weakly prime, because it can be changed into another prime (681720187) 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, 340863593 + 340863594.

It is an arithmetic number, because the mean of its divisors is an integer number (340863594).

Almost surely, 2^681727187 is an apocalyptic number.

681727187 is a deficient number, since it is larger than the sum of its proper divisors (1).

681727187 is an equidigital number, since it uses as much as digits as its factorization.

681727187 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 263424, while the sum is 47.

The square root of 681727187 is about 26109.9059171036. The cubic root of 681727187 is about 880.1098291812.

Subtracting 681727187 from its reverse (781727186), we obtain a palindrome (99999999).

The spelling of 681727187 in words is "six hundred eighty-one million, seven hundred twenty-seven thousand, one hundred eighty-seven".