684637 has 2 divisors, whose sum is σ = 684638. Its totient is φ = 684636.

The previous prime is 684617. The next prime is 684643. The reversal of 684637 is 736486.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 443556 + 241081 = 666^2 + 491^2 .

It is a cyclic number.

It is not a de Polignac number, because 684637 - 2¹⁵ = 651869 is a prime.

684637 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (684617) 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, 342318 + 342319.

It is an arithmetic number, because the mean of its divisors is an integer number (342319).

2⁶⁸⁴⁶³⁷ is an apocalyptic number.

It is an amenable number.

684637 is a deficient number, since it is larger than the sum of its proper divisors (1).

684637 is an equidigital number, since it uses as much as digits as its factorization.

684637 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 24192, while the sum is 34.

The square root of 684637 is about 827.4279424820. The cubic root of 684637 is about 88.1360241394.

The spelling of 684637 in words is "six hundred eighty-four thousand, six hundred thirty-seven".