680561 has 24 divisors (see below), whose sum is σ = 902880. Its totient is φ = 508032.

The previous prime is 680539. The next prime is 680567. The reversal of 680561 is 165086.

680561 = 93² + 94² + ... + 141².

It is not a de Polignac number, because 680561 - 2¹⁰ = 679537 is a prime.

It is an Ulam number.

680561 is a modest number, since divided by 561 gives 68 as remainder.

It is a Curzon number.

It is a nialpdrome in base 7.

It is a self number, because there is not a number n which added to its sum of digits gives 680561.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 680561.

It is not an unprimeable number, because it can be changed into a prime (680567) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 15806 + ... + 15848.

It is an arithmetic number, because the mean of its divisors is an integer number (37620).

2⁶⁸⁰⁵⁶¹ is an apocalyptic number.

It is an amenable number.

680561 is a deficient number, since it is larger than the sum of its proper divisors (222319).

680561 is a wasteful number, since it uses less digits than its factorization.

680561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 93 (or 86 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 26.

The square root of 680561 is about 824.9612112094. The cubic root of 680561 is about 87.9607693592.

The spelling of 680561 in words is "six hundred eighty thousand, five hundred sixty-one".