681494791 has 2 divisors, whose sum is σ = 681494792. Its totient is φ = 681494790.

The previous prime is 681494771. The next prime is 681494797. The reversal of 681494791 is 197494186.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 681494791 - 2¹⁷ = 681363719 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (681494797) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 340747395 + 340747396.

It is an arithmetic number, because the mean of its divisors is an integer number (340747396).

Almost surely, 2^681494791 is an apocalyptic number.

681494791 is a deficient number, since it is larger than the sum of its proper divisors (1).

681494791 is an equidigital number, since it uses as much as digits as its factorization.

681494791 is an evil number, because the sum of its binary digits is even.

The product of its digits is 435456, while the sum is 49.

The square root of 681494791 is about 26105.4551961846. The cubic root of 681494791 is about 880.0098100663.

The spelling of 681494791 in words is "six hundred eighty-one million, four hundred ninety-four thousand, seven hundred ninety-one".