638307647 has 2 divisors, whose sum is σ = 638307648. Its totient is φ = 638307646.

The previous prime is 638307643. The next prime is 638307667. The reversal of 638307647 is 746703836.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 638307647 - 2² = 638307643 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 638307598 and 638307607.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (638307643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319153823 + 319153824.

It is an arithmetic number, because the mean of its divisors is an integer number (319153824).

Almost surely, 2^638307647 is an apocalyptic number.

638307647 is a deficient number, since it is larger than the sum of its proper divisors (1).

638307647 is an equidigital number, since it uses as much as digits as its factorization.

638307647 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 508032, while the sum is 44.

The square root of 638307647 is about 25264.7510773409. The cubic root of 638307647 is about 861.0136088243.

The spelling of 638307647 in words is "six hundred thirty-eight million, three hundred seven thousand, six hundred forty-seven".