638890 has 16 divisors (see below), whose sum is σ = 1314432. Its totient is φ = 219024.

The previous prime is 638861. The next prime is 638893. The reversal of 638890 is 98836.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638893) by changing a digit.

638890 is an untouchable number, because it is not equal to the sum of proper divisors of any 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 7 ways as a sum of consecutive naturals, for example, 4494 + ... + 4633.

It is an arithmetic number, because the mean of its divisors is an integer number (82152).

2⁶³⁸⁸⁹⁰ is an apocalyptic number.

638890 is an abundant number, since it is smaller than the sum of its proper divisors (675542).

It is a weird number, because it is abundant, but not a pseudoperfect number.

638890 is a wasteful number, since it uses less digits than its factorization.

638890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9141.

The product of its (nonzero) digits is 10368, while the sum is 34.

The square root of 638890 is about 799.3059489332. The cubic root of 638890 is about 86.1275374683.

The spelling of 638890 in words is "six hundred thirty-eight thousand, eight hundred ninety".