681764 has 6 divisors (see below), whose sum is σ = 1193094. Its totient is φ = 340880.

The previous prime is 681763. The next prime is 681773. The reversal of 681764 is 467186.

It can be written as a sum of positive squares in only one way, i.e., 652864 + 28900 = 808^2 + 170^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 681764.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 681764.

It is not an unprimeable number, because it can be changed into a prime (681763) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 85217 + ... + 85224.

It is an arithmetic number, because the mean of its divisors is an integer number (198849).

2⁶⁸¹⁷⁶⁴ is an apocalyptic number.

It is an amenable number.

681764 is a deficient number, since it is larger than the sum of its proper divisors (511330).

681764 is a wasteful number, since it uses less digits than its factorization.

681764 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 170445 (or 170443 counting only the distinct ones).

The product of its digits is 8064, while the sum is 32.

The square root of 681764 is about 825.6900144727. The cubic root of 681764 is about 88.0125670758.

The spelling of 681764 in words is "six hundred eighty-one thousand, seven hundred sixty-four".