681445 has 8 divisors (see below), whose sum is σ = 865944. Its totient is φ = 513024.

The previous prime is 681427. The next prime is 681449. The reversal of 681445 is 544186.

It can be written as a sum of positive squares in 4 ways, for example, as 161604 + 519841 = 402^2 + 721^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 681445 - 2¹⁵ = 648677 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (681449) 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 in 7 ways as a sum of consecutive naturals, for example, 3924 + ... + 4093.

It is an arithmetic number, because the mean of its divisors is an integer number (108243).

2⁶⁸¹⁴⁴⁵ is an apocalyptic number.

It is an amenable number.

681445 is a deficient number, since it is larger than the sum of its proper divisors (184499).

681445 is a wasteful number, since it uses less digits than its factorization.

681445 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8039.

The product of its digits is 3840, while the sum is 28.

The square root of 681445 is about 825.4968201029. The cubic root of 681445 is about 87.9988377946.

It can be divided in two parts, 6814 and 45, that added together give a cube (6859 = 19³).

The spelling of 681445 in words is "six hundred eighty-one thousand, four hundred forty-five".