1643428 has 6 divisors (see below), whose sum is σ = 2876006. Its totient is φ = 821712.

The previous prime is 1643423. The next prime is 1643431. The reversal of 1643428 is 8243461.

It can be written as a sum of positive squares in only one way, i.e., 1183744 + 459684 = 1088^2 + 678^2 .

It is a junction number, because it is equal to n+sod(n) for n = 1643396 and 1643405.

It is not an unprimeable number, because it can be changed into a prime (1643423) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 205425 + ... + 205432.

2^1643428 is an apocalyptic number.

It is an amenable number.

1643428 is a deficient number, since it is larger than the sum of its proper divisors (1232578).

1643428 is a wasteful number, since it uses less digits than its factorization.

1643428 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 410861 (or 410859 counting only the distinct ones).

The product of its digits is 4608, while the sum is 28.

The square root of 1643428 is about 1281.9625579556. The cubic root of 1643428 is about 118.0094792730.

Adding to 1643428 its reverse (8243461), we get a palindrome (9886889).

The spelling of 1643428 in words is "one million, six hundred forty-three thousand, four hundred twenty-eight".