678641 has 2 divisors, whose sum is σ = 678642. Its totient is φ = 678640.

The previous prime is 678637. The next prime is 678647. The reversal of 678641 is 146876.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 672400 + 6241 = 820^2 + 79^2 .

It is a cyclic number.

It is not a de Polignac number, because 678641 - 2² = 678637 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 678598 and 678607.

It is not a weakly prime, because it can be changed into another prime (678647) 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, 339320 + 339321.

It is an arithmetic number, because the mean of its divisors is an integer number (339321).

2⁶⁷⁸⁶⁴¹ is an apocalyptic number.

It is an amenable number.

678641 is a deficient number, since it is larger than the sum of its proper divisors (1).

678641 is an equidigital number, since it uses as much as digits as its factorization.

678641 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8064, while the sum is 32.

The square root of 678641 is about 823.7966982211. The cubic root of 678641 is about 87.8779730848.

The spelling of 678641 in words is "six hundred seventy-eight thousand, six hundred forty-one".