681000191 has 2 divisors, whose sum is σ = 681000192. Its totient is φ = 681000190.

The previous prime is 681000167. The next prime is 681000209. The reversal of 681000191 is 191000186.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-681000191 is a prime.

It is a super-2 number, since 2×681000191² = 927522520284072962, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 681000191.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (681000091) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 340500095 + 340500096.

It is an arithmetic number, because the mean of its divisors is an integer number (340500096).

Almost surely, 2^681000191 is an apocalyptic number.

681000191 is a deficient number, since it is larger than the sum of its proper divisors (1).

681000191 is an equidigital number, since it uses as much as digits as its factorization.

681000191 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 432, while the sum is 26.

The square root of 681000191 is about 26095.9803609675. The cubic root of 681000191 is about 879.7968672841.

The spelling of 681000191 in words is "six hundred eighty-one million, one hundred ninety-one", and thus it is an aban number.