638365 has 32 divisors (see below), whose sum is σ = 999936. Its totient is φ = 380160.

The previous prime is 638359. The next prime is 638371. The reversal of 638365 is 563836.

638365 = T₇₀ + T₇₁ + ... + T₁₆₀.

It is an interprime number because it is at equal distance from previous prime (638359) and next prime (638371).

It is not a de Polignac number, because 638365 - 2¹⁵ = 605597 is a prime.

It is an Ulam number.

It is an alternating number because its digits alternate between even and odd.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 10435 + ... + 10495.

It is an arithmetic number, because the mean of its divisors is an integer number (31248).

2⁶³⁸³⁶⁵ is an apocalyptic number.

638365 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

638365 is a deficient number, since it is larger than the sum of its proper divisors (361571).

638365 is a wasteful number, since it uses less digits than its factorization.

638365 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109.

The product of its digits is 12960, while the sum is 31.

The square root of 638365 is about 798.9774715222. The cubic root of 638365 is about 86.1039395885.

Subtracting from 638365 its reverse (563836), we obtain a square (74529 = 273²).

The spelling of 638365 in words is "six hundred thirty-eight thousand, three hundred sixty-five".