681978 has 16 divisors (see below), whose sum is σ = 1488096. Its totient is φ = 206640.

The previous prime is 681977. The next prime is 681979. The reversal of 681978 is 879186.

It is an interprime number because it is at equal distance from previous prime (681977) and next prime (681979).

It is not an unprimeable number, because it can be changed into a prime (681971) 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, 5101 + ... + 5232.

It is an arithmetic number, because the mean of its divisors is an integer number (93006).

2⁶⁸¹⁹⁷⁸ is an apocalyptic number.

681978 is an abundant number, since it is smaller than the sum of its proper divisors (806118).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

681978 is a wasteful number, since it uses less digits than its factorization.

681978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10349.

The product of its digits is 24192, while the sum is 39.

The square root of 681978 is about 825.8195928894. The cubic root of 681978 is about 88.0217749146.

The spelling of 681978 in words is "six hundred eighty-one thousand, nine hundred seventy-eight".