681613 has 2 divisors, whose sum is σ = 681614. Its totient is φ = 681612.

The previous prime is 681607. The next prime is 681623. The reversal of 681613 is 316186.

681613 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 675684 + 5929 = 822^2 + 77^2 .

It is a cyclic number.

It is not a de Polignac number, because 681613 - 2¹⁷ = 550541 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (681623) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 340806 + 340807.

It is an arithmetic number, because the mean of its divisors is an integer number (340807).

2⁶⁸¹⁶¹³ is an apocalyptic number.

It is an amenable number.

681613 is a deficient number, since it is larger than the sum of its proper divisors (1).

681613 is an equidigital number, since it uses as much as digits as its factorization.

681613 is an evil number, because the sum of its binary digits is even.

The product of its digits is 864, while the sum is 25.

The square root of 681613 is about 825.5985707352. The cubic root of 681613 is about 88.0060687963.

Adding to 681613 its reverse (316186), we get a palindrome (997799).

It can be divided in two parts, 68 and 1613, that added together give a square (1681 = 41²).

The spelling of 681613 in words is "six hundred eighty-one thousand, six hundred thirteen".