688939 has 2 divisors, whose sum is σ = 688940. Its totient is φ = 688938.

The previous prime is 688907. The next prime is 688951. The reversal of 688939 is 939886.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 688939 - 2⁵ = 688907 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 688895 and 688904.

It is not a weakly prime, because it can be changed into another prime (688969) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 344469 + 344470.

It is an arithmetic number, because the mean of its divisors is an integer number (344470).

2⁶⁸⁸⁹³⁹ is an apocalyptic number.

688939 is a deficient number, since it is larger than the sum of its proper divisors (1).

688939 is an equidigital number, since it uses as much as digits as its factorization.

688939 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 93312, while the sum is 43.

The square root of 688939 is about 830.0234936434. The cubic root of 688939 is about 88.3202433038.

The spelling of 688939 in words is "six hundred eighty-eight thousand, nine hundred thirty-nine".