638723171 has 8 divisors (see below), whose sum is σ = 681811200. Its totient is φ = 596582280.

The previous prime is 638723153. The next prime is 638723191. The reversal of 638723171 is 171327836.

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

It is a cyclic number.

It is not a de Polignac number, because 638723171 - 2¹⁴ = 638706787 is a prime.

It is not an unprimeable number, because it can be changed into a prime (638723191) 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 7 ways as a sum of consecutive naturals, for example, 235391 + ... + 238088.

It is an arithmetic number, because the mean of its divisors is an integer number (85226400).

Almost surely, 2^638723171 is an apocalyptic number.

638723171 is a deficient number, since it is larger than the sum of its proper divisors (43088029).

638723171 is a wasteful number, since it uses less digits than its factorization.

638723171 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 473569.

The product of its digits is 42336, while the sum is 38.

The square root of 638723171 is about 25272.9731333692. The cubic root of 638723171 is about 861.2004018306.

The spelling of 638723171 in words is "six hundred thirty-eight million, seven hundred twenty-three thousand, one hundred seventy-one".