678581 has 2 divisors, whose sum is σ = 678582. Its totient is φ = 678580.

The previous prime is 678577. The next prime is 678593. The reversal of 678581 is 185876.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 625681 + 52900 = 791^2 + 230^2 .

It is a cyclic number.

It is not a de Polignac number, because 678581 - 2² = 678577 is a prime.

It is a super-2 number, since 2×678581² = 920944347122, which contains 22 as substring.

It is a Sophie Germain prime.

It is an alternating number because its digits alternate between even and odd.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (678541) 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, 339290 + 339291.

It is an arithmetic number, because the mean of its divisors is an integer number (339291).

2⁶⁷⁸⁵⁸¹ is an apocalyptic number.

It is an amenable number.

678581 is a deficient number, since it is larger than the sum of its proper divisors (1).

678581 is an equidigital number, since it uses as much as digits as its factorization.

678581 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13440, while the sum is 35.

The square root of 678581 is about 823.7602806642. The cubic root of 678581 is about 87.8753831864.

It can be divided in two parts, 6 and 78581, that added together give a palindrome (78587).

The spelling of 678581 in words is "six hundred seventy-eight thousand, five hundred eighty-one".