1680978 has 32 divisors (see below), whose sum is σ = 3782016. Its totient is φ = 494208.

The previous prime is 1680967. The next prime is 1680979. The reversal of 1680978 is 8790861.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is not an unprimeable number, because it can be changed into a prime (1680979) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1326 + ... + 2262.

It is an arithmetic number, because the mean of its divisors is an integer number (118188).

2^1680978 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1680978, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1891008).

1680978 is an abundant number, since it is smaller than the sum of its proper divisors (2101038).

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

1680978 is a wasteful number, since it uses less digits than its factorization.

1680978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 978.

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

The square root of 1680978 is about 1296.5253564817. The cubic root of 1680978 is about 118.9015026585.

The spelling of 1680978 in words is "one million, six hundred eighty thousand, nine hundred seventy-eight".