638829 has 6 divisors (see below), whose sum is σ = 922766. Its totient is φ = 425880.

The previous prime is 638819. The next prime is 638839. The reversal of 638829 is 928836.

It is an interprime number because it is at equal distance from previous prime (638819) and next prime (638839).

It can be written as a sum of positive squares in only one way, i.e., 636804 + 2025 = 798^2 + 45^2 .

It is not a de Polignac number, because 638829 - 2⁹ = 638317 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 638793 and 638802.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 638829.

It is not an unprimeable number, because it can be changed into a prime (638819) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 35482 + ... + 35499.

2⁶³⁸⁸²⁹ is an apocalyptic number.

It is an amenable number.

638829 is a deficient number, since it is larger than the sum of its proper divisors (283937).

638829 is a wasteful number, since it uses less digits than its factorization.

638829 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 70987 (or 70984 counting only the distinct ones).

The product of its digits is 20736, while the sum is 36.

The square root of 638829 is about 799.2677899177. The cubic root of 638829 is about 86.1247962834.

The spelling of 638829 in words is "six hundred thirty-eight thousand, eight hundred twenty-nine".