681493 has 2 divisors, whose sum is σ = 681494. Its totient is φ = 681492.

The previous prime is 681487. The next prime is 681497. The reversal of 681493 is 394186.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 574564 + 106929 = 758^2 + 327^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-681493 is a prime.

681493 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (681497) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 340746 + 340747.

It is an arithmetic number, because the mean of its divisors is an integer number (340747).

2⁶⁸¹⁴⁹³ is an apocalyptic number.

It is an amenable number.

681493 is a deficient number, since it is larger than the sum of its proper divisors (1).

681493 is an equidigital number, since it uses as much as digits as its factorization.

681493 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5184, while the sum is 31.

The square root of 681493 is about 825.5258929919. The cubic root of 681493 is about 88.0009039163. Note that the first 3 decimals are identical.

The spelling of 681493 in words is "six hundred eighty-one thousand, four hundred ninety-three".