1680447 has 4 divisors (see below), whose sum is σ = 2240600. Its totient is φ = 1120296.

The previous prime is 1680439. The next prime is 1680457. The reversal of 1680447 is 7440861.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 7440861 = 3 ⋅2480287.

It is not a de Polignac number, because 1680447 - 2³ = 1680439 is a prime.

It is an Ulam number.

It is a D-number.

It is a Duffinian number.

1680447 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1680407) 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, 280072 + ... + 280077.

It is an arithmetic number, because the mean of its divisors is an integer number (560150).

2^1680447 is an apocalyptic number.

1680447 is a deficient number, since it is larger than the sum of its proper divisors (560153).

1680447 is an equidigital number, since it uses as much as digits as its factorization.

1680447 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 560152.

The product of its (nonzero) digits is 5376, while the sum is 30.

The square root of 1680447 is about 1296.3205622067. The cubic root of 1680447 is about 118.8889815057. Note that the first 3 decimals are identical.

The spelling of 1680447 in words is "one million, six hundred eighty thousand, four hundred forty-seven".