687637 has 2 divisors, whose sum is σ = 687638. Its totient is φ = 687636.

The previous prime is 687623. The next prime is 687641. The reversal of 687637 is 736786.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 576081 + 111556 = 759^2 + 334^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-687637 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 687596 and 687605.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (687647) 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, 343818 + 343819.

It is an arithmetic number, because the mean of its divisors is an integer number (343819).

2⁶⁸⁷⁶³⁷ is an apocalyptic number.

It is an amenable number.

687637 is a deficient number, since it is larger than the sum of its proper divisors (1).

687637 is an equidigital number, since it uses as much as digits as its factorization.

687637 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 42336, while the sum is 37.

The square root of 687637 is about 829.2388075820. The cubic root of 687637 is about 88.2645705116.

The spelling of 687637 in words is "six hundred eighty-seven thousand, six hundred thirty-seven".