688729 has 2 divisors, whose sum is σ = 688730. Its totient is φ = 688728.

The previous prime is 688717. The next prime is 688733. The reversal of 688729 is 927886.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 458329 + 230400 = 677^2 + 480^2 .

It is a cyclic number.

It is not a de Polignac number, because 688729 - 2⁵ = 688697 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 688691 and 688700.

It is not a weakly prime, because it can be changed into another prime (688799) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 344364 + 344365.

It is an arithmetic number, because the mean of its divisors is an integer number (344365).

2⁶⁸⁸⁷²⁹ is an apocalyptic number.

It is an amenable number.

688729 is a deficient number, since it is larger than the sum of its proper divisors (1).

688729 is an equidigital number, since it uses as much as digits as its factorization.

688729 is an evil number, because the sum of its binary digits is even.

The product of its digits is 48384, while the sum is 40.

The square root of 688729 is about 829.8969815586. The cubic root of 688729 is about 88.3112685683.

The spelling of 688729 in words is "six hundred eighty-eight thousand, seven hundred twenty-nine".