681305893 has 2 divisors, whose sum is σ = 681305894. Its totient is φ = 681305892.

The previous prime is 681305887. The next prime is 681305921. The reversal of 681305893 is 398503186.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 652393764 + 28912129 = 25542^2 + 5377^2 .

It is a cyclic number.

It is not a de Polignac number, because 681305893 - 2¹⁷ = 681174821 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (681305813) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 340652946 + 340652947.

It is an arithmetic number, because the mean of its divisors is an integer number (340652947).

Almost surely, 2^681305893 is an apocalyptic number.

It is an amenable number.

681305893 is a deficient number, since it is larger than the sum of its proper divisors (1).

681305893 is an equidigital number, since it uses as much as digits as its factorization.

681305893 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 155520, while the sum is 43.

The square root of 681305893 is about 26101.8369660068. The cubic root of 681305893 is about 879.9284949648.

The spelling of 681305893 in words is "six hundred eighty-one million, three hundred five thousand, eight hundred ninety-three".