1680981 has 8 divisors (see below), whose sum is σ = 2250720. Its totient is φ = 1115952.

The previous prime is 1680979. The next prime is 1680983. The reversal of 1680981 is 1890861.

It is an interprime number because it is at equal distance from previous prime (1680979) and next prime (1680983).

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

It is not a de Polignac number, because 1680981 - 2¹ = 1680979 is a prime.

It is a super-3 number, since 3×1680981³ = 14249829523330548423, which contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1680983) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 235 + ... + 1848.

It is an arithmetic number, because the mean of its divisors is an integer number (281340).

2^1680981 is an apocalyptic number.

It is an amenable number.

1680981 is a deficient number, since it is larger than the sum of its proper divisors (569739).

1680981 is a wasteful number, since it uses less digits than its factorization.

1680981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2355.

The product of its (nonzero) digits is 3456, while the sum is 33.

The square root of 1680981 is about 1296.5265134196. The cubic root of 1680981 is about 118.9015733919.

The spelling of 1680981 in words is "one million, six hundred eighty thousand, nine hundred eighty-one".