1638943 has 2 divisors, whose sum is σ = 1638944. Its totient is φ = 1638942.

The previous prime is 1638929. The next prime is 1638947. The reversal of 1638943 is 3498361.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1638943 - 2⁹ = 1638431 is a prime.

It is a super-2 number, since 2×1638943² = 5372268314498, which contains 22 as substring.

It is an alternating number because its digits alternate between odd and even.

It is a junction number, because it is equal to n+sod(n) for n = 1638899 and 1638908.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1638947) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 819471 + 819472.

It is an arithmetic number, because the mean of its divisors is an integer number (819472).

2^1638943 is an apocalyptic number.

1638943 is a deficient number, since it is larger than the sum of its proper divisors (1).

1638943 is an equidigital number, since it uses as much as digits as its factorization.

1638943 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 15552, while the sum is 34.

The square root of 1638943 is about 1280.2120918035. The cubic root of 1638943 is about 117.9020301450.

The spelling of 1638943 in words is "one million, six hundred thirty-eight thousand, nine hundred forty-three".