638995 has 8 divisors (see below), whose sum is σ = 876384. Its totient is φ = 438144.

The previous prime is 638993. The next prime is 638999. The reversal of 638995 is 599836.

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

It is not a de Polignac number, because 638995 - 2¹ = 638993 is a prime.

It is a super-2 number, since 2×638995² = 816629220050, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (638993) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9094 + ... + 9163.

It is an arithmetic number, because the mean of its divisors is an integer number (109548).

2⁶³⁸⁹⁹⁵ is an apocalyptic number.

638995 is a deficient number, since it is larger than the sum of its proper divisors (237389).

638995 is a wasteful number, since it uses less digits than its factorization.

638995 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18269.

The product of its digits is 58320, while the sum is 40.

The square root of 638995 is about 799.3716282181. The cubic root of 638995 is about 86.1322554929.

The spelling of 638995 in words is "six hundred thirty-eight thousand, nine hundred ninety-five".