638340943 has 2 divisors, whose sum is σ = 638340944. Its totient is φ = 638340942.

The previous prime is 638340889. The next prime is 638340947. The reversal of 638340943 is 349043836.

638340943 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-638340943 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 638340896 and 638340905.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (638340947) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319170471 + 319170472.

It is an arithmetic number, because the mean of its divisors is an integer number (319170472).

Almost surely, 2^638340943 is an apocalyptic number.

638340943 is a deficient number, since it is larger than the sum of its proper divisors (1).

638340943 is an equidigital number, since it uses as much as digits as its factorization.

638340943 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 186624, while the sum is 40.

The square root of 638340943 is about 25265.4100105262. The cubic root of 638340943 is about 861.0285795628.

The spelling of 638340943 in words is "six hundred thirty-eight million, three hundred forty thousand, nine hundred forty-three".