1643328 has 70 divisors (see below), whose sum is σ = 4886706. Its totient is φ = 546048.

The previous prime is 1643311. The next prime is 1643347. The reversal of 1643328 is 8233461.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 1016064 + 627264 = 1008^2 + 792^2 .

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

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 9 ways as a sum of consecutive naturals, for example, 5026 + ... + 5342.

2^1643328 is an apocalyptic number.

1643328 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1643328, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2443353).

1643328 is an abundant number, since it is smaller than the sum of its proper divisors (3243378).

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

1643328 is an equidigital number, since it uses as much as digits as its factorization.

1643328 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 341 (or 322 counting only the distinct ones).

The product of its digits is 3456, while the sum is 27.

The square root of 1643328 is about 1281.9235546631. The cubic root of 1643328 is about 118.0070856609.

Adding to 1643328 its reverse (8233461), we get a palindrome (9876789).

It can be divided in two parts, 16433 and 28, that added together give a palindrome (16461).

The spelling of 1643328 in words is "one million, six hundred forty-three thousand, three hundred twenty-eight".