638543217 has 8 divisors (see below), whose sum is σ = 916882624. Its totient is φ = 392949648.

The previous prime is 638543189. The next prime is 638543221. The reversal of 638543217 is 712345836.

638543217 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 638543217 - 2¹⁰ = 638542193 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39), and also a Moran number because the ratio is a prime number: 16372903 = 638543217 / (6 + 3 + 8 + 5 + 4 + 3 + 2 + 1 + 7).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (638543267) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8186413 + ... + 8186490.

It is an arithmetic number, because the mean of its divisors is an integer number (114610328).

Almost surely, 2^638543217 is an apocalyptic number.

It is an amenable number.

638543217 is a deficient number, since it is larger than the sum of its proper divisors (278339407).

638543217 is a wasteful number, since it uses less digits than its factorization.

638543217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16372919.

The product of its digits is 120960, while the sum is 39.

The square root of 638543217 is about 25269.4126761981. The cubic root of 638543217 is about 861.1195159733.

The spelling of 638543217 in words is "six hundred thirty-eight million, five hundred forty-three thousand, two hundred seventeen".