681316693 has 2 divisors, whose sum is σ = 681316694. Its totient is φ = 681316692.

The previous prime is 681316637. The next prime is 681316717. The reversal of 681316693 is 396613186.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 462809169 + 218507524 = 21513^2 + 14782^2 .

It is a cyclic number.

It is not a de Polignac number, because 681316693 - 2²⁵ = 647762261 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (681314693) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 340658346 + 340658347.

It is an arithmetic number, because the mean of its divisors is an integer number (340658347).

Almost surely, 2^681316693 is an apocalyptic number.

It is an amenable number.

681316693 is a deficient number, since it is larger than the sum of its proper divisors (1).

681316693 is an equidigital number, since it uses as much as digits as its factorization.

681316693 is an evil number, because the sum of its binary digits is even.

The product of its digits is 139968, while the sum is 43.

The square root of 681316693 is about 26102.0438471779. The cubic root of 681316693 is about 879.9331444561.

The spelling of 681316693 in words is "six hundred eighty-one million, three hundred sixteen thousand, six hundred ninety-three".