6638643 has 12 divisors (see below), whose sum is σ = 10461048. Its totient is φ = 4023360.

The previous prime is 6638633. The next prime is 6638647. The reversal of 6638643 is 3468366.

6638643 is a `hidden beast` number, since 6 + 6 + 3 + 8 + 643 = 666.

It is not a de Polignac number, because 6638643 - 2⁴ = 6638627 is a prime.

It is an Ulam number.

It is a junction number, because it is equal to n+sod(n) for n = 6638598 and 6638607.

It is not an unprimeable number, because it can be changed into a prime (6638647) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 33430 + ... + 33627.

It is an arithmetic number, because the mean of its divisors is an integer number (871754).

Almost surely, 2^6638643 is an apocalyptic number.

6638643 is a deficient number, since it is larger than the sum of its proper divisors (3822405).

6638643 is a wasteful number, since it uses less digits than its factorization.

6638643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67074 (or 67071 counting only the distinct ones).

The product of its digits is 62208, while the sum is 36.

The square root of 6638643 is about 2576.5564228249. The cubic root of 6638643 is about 187.9431226009.

The spelling of 6638643 in words is "six million, six hundred thirty-eight thousand, six hundred forty-three".