681517 has 4 divisors (see below), whose sum is σ = 686560. Its totient is φ = 676476.

The previous prime is 681497. The next prime is 681521. The reversal of 681517 is 715186.

It is a happy number.

681517 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 715186 = 2 ⋅357593.

It is a cyclic number.

It is not a de Polignac number, because 681517 - 2¹⁹ = 157229 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 (681557) 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, 2313 + ... + 2590.

It is an arithmetic number, because the mean of its divisors is an integer number (171640).

2⁶⁸¹⁵¹⁷ is an apocalyptic number.

It is an amenable number.

681517 is a deficient number, since it is larger than the sum of its proper divisors (5043).

681517 is a wasteful number, since it uses less digits than its factorization.

681517 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5042.

The product of its digits is 1680, while the sum is 28.

The square root of 681517 is about 825.5404290524. The cubic root of 681517 is about 88.0019369408.

The spelling of 681517 in words is "six hundred eighty-one thousand, five hundred seventeen".