1646 has 4 divisors (see below), whose sum is σ = 2472. Its totient is φ = 822.

The previous prime is 1637. The next prime is 1657. The reversal of 1646 is 6461.

1646 is nontrivially palindromic in base 14.

1646 is digitally balanced in base 5, because in such base it contains all the possibile digits an equal number of times.

1646 is an esthetic number in base 4, because in such base its adjacent digits differ by 1.

It is a semiprime because it is the product of two primes.

It is an Ulam number.

1646 is an undulating number in base 14.

1646 is strictly pandigital in base 5.

It is a plaindrome in base 9, base 11 and base 16.

It is a nialpdrome in base 12 and base 13.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 1646.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410 + ... + 413.

It is an arithmetic number, because the mean of its divisors is an integer number (618).

1646 is a deficient number, since it is larger than the sum of its proper divisors (826).

1646 is an equidigital number, since it uses as much as digits as its factorization.

1646 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 825.

The product of its digits is 144, while the sum is 17.

The square root of 1646 is about 40.5709255502. The cubic root of 1646 is about 11.8071009639.

The spelling of 1646 in words is "one thousand, six hundred forty-six".