681601 has 4 divisors (see below), whose sum is σ = 691012. Its totient is φ = 672192.

The previous prime is 681589. The next prime is 681607. The reversal of 681601 is 106186.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 106186 = 2 ⋅53093.

It can be written as a sum of positive squares in 2 ways, for example, as 540225 + 141376 = 735^2 + 376^2 .

It is a cyclic number.

It is not a de Polignac number, because 681601 - 2⁹ = 681089 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (681607) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4596 + ... + 4741.

It is an arithmetic number, because the mean of its divisors is an integer number (172753).

2⁶⁸¹⁶⁰¹ is an apocalyptic number.

It is an amenable number.

681601 is a deficient number, since it is larger than the sum of its proper divisors (9411).

681601 is an equidigital number, since it uses as much as digits as its factorization.

681601 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9410.

The product of its (nonzero) digits is 288, while the sum is 22.

The square root of 681601 is about 825.5913032488. The cubic root of 681601 is about 88.0055523356.

Adding to 681601 its reverse (106186), we get a palindrome (787787).

The spelling of 681601 in words is "six hundred eighty-one thousand, six hundred one".