681663 has 8 divisors (see below), whose sum is σ = 956800. Its totient is φ = 430488.

The previous prime is 681647. The next prime is 681673. The reversal of 681663 is 366186.

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

It is not a de Polignac number, because 681663 - 2⁴ = 681647 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 681663.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (681613) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5923 + ... + 6036.

It is an arithmetic number, because the mean of its divisors is an integer number (119600).

2⁶⁸¹⁶⁶³ is an apocalyptic number.

681663 is a deficient number, since it is larger than the sum of its proper divisors (275137).

681663 is a wasteful number, since it uses less digits than its factorization.

681663 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11981.

The product of its digits is 5184, while the sum is 30.

The square root of 681663 is about 825.6288512401. The cubic root of 681663 is about 88.0082206508.

The spelling of 681663 in words is "six hundred eighty-one thousand, six hundred sixty-three".