688642529 has 2 divisors, whose sum is σ = 688642530. Its totient is φ = 688642528.

The previous prime is 688642523. The next prime is 688642531. The reversal of 688642529 is 925246886.

688642529 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 678498304 + 10144225 = 26048^2 + 3185^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-688642529 is a prime.

Together with 688642531, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (688642523) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 344321264 + 344321265.

It is an arithmetic number, because the mean of its divisors is an integer number (344321265).

Almost surely, 2^688642529 is an apocalyptic number.

It is an amenable number.

688642529 is a deficient number, since it is larger than the sum of its proper divisors (1).

688642529 is an equidigital number, since it uses as much as digits as its factorization.

688642529 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1658880, while the sum is 50.

The square root of 688642529 is about 26241.9993331301. Note that the first 3 decimals coincide. The cubic root of 688642529 is about 883.0757254107.

The spelling of 688642529 in words is "six hundred eighty-eight million, six hundred forty-two thousand, five hundred twenty-nine".