1680989 has 4 divisors (see below), whose sum is σ = 1690560. Its totient is φ = 1671420.

The previous prime is 1680983. The next prime is 1681003. The reversal of 1680989 is 9890861.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1680989 - 2¹² = 1676893 is a prime.

It is a Duffinian 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 polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4517 + ... + 4874.

It is an arithmetic number, because the mean of its divisors is an integer number (422640).

2^1680989 is an apocalyptic number.

It is an amenable number.

1680989 is a deficient number, since it is larger than the sum of its proper divisors (9571).

1680989 is an equidigital number, since it uses as much as digits as its factorization.

1680989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9570.

The product of its (nonzero) digits is 31104, while the sum is 41.

The square root of 1680989 is about 1296.5295985823. The cubic root of 1680989 is about 118.9017620142.

The spelling of 1680989 in words is "one million, six hundred eighty thousand, nine hundred eighty-nine".