1641664 has 28 divisors (see below), whose sum is σ = 3300984. Its totient is φ = 809984.

The previous prime is 1641659. The next prime is 1641709. The reversal of 1641664 is 4661461.

It is a Smith number, since the sum of its digits (28) coincides with the sum of the digits of its prime factors.

It is a zygodrome in base 15.

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 in 3 ways as a sum of consecutive naturals, for example, 7119 + ... + 7345.

2^1641664 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1641664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1650492).

1641664 is an abundant number, since it is smaller than the sum of its proper divisors (1659320).

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

1641664 is a wasteful number, since it uses less digits than its factorization.

1641664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 352 (or 342 counting only the distinct ones).

The product of its digits is 3456, while the sum is 28.

The square root of 1641664 is about 1281.2743656220. The cubic root of 1641664 is about 117.9672416967.

The spelling of 1641664 in words is "one million, six hundred forty-one thousand, six hundred sixty-four".