688637 has 2 divisors, whose sum is σ = 688638. Its totient is φ = 688636.

The previous prime is 688631. The next prime is 688657. The reversal of 688637 is 736886.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 606841 + 81796 = 779^2 + 286^2 .

It is a cyclic number.

It is not a de Polignac number, because 688637 - 2⁴ = 688621 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 688637.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (688631) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 344318 + 344319.

It is an arithmetic number, because the mean of its divisors is an integer number (344319).

2⁶⁸⁸⁶³⁷ is an apocalyptic number.

It is an amenable number.

688637 is a deficient number, since it is larger than the sum of its proper divisors (1).

688637 is an equidigital number, since it uses as much as digits as its factorization.

688637 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 48384, while the sum is 38.

The square root of 688637 is about 829.8415511409. The cubic root of 688637 is about 88.3073362047.

The spelling of 688637 in words is "six hundred eighty-eight thousand, six hundred thirty-seven".