681523 has 2 divisors, whose sum is σ = 681524. Its totient is φ = 681522.

The previous prime is 681521. The next prime is 681539. The reversal of 681523 is 325186.

It is a happy number.

681523 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 is a cyclic number.

It is not a de Polignac number, because 681523 - 2¹ = 681521 is a prime.

Together with 681521, it forms a pair of twin primes.

681523 is a lucky number.

It is a plaindrome in base 9.

It is a nialpdrome in base 16.

It is not a weakly prime, because it can be changed into another prime (681521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 340761 + 340762.

It is an arithmetic number, because the mean of its divisors is an integer number (340762).

681523 is a Friedman number, since it can be written as 51+(82+6)^3, using all its digits and the basic arithmetic operations.

2⁶⁸¹⁵²³ is an apocalyptic number.

681523 is a deficient number, since it is larger than the sum of its proper divisors (1).

681523 is an equidigital number, since it uses as much as digits as its factorization.

681523 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1440, while the sum is 25.

The square root of 681523 is about 825.5440630275. The cubic root of 681523 is about 88.0021951932.

The spelling of 681523 in words is "six hundred eighty-one thousand, five hundred twenty-three".