638984 has 8 divisors (see below), whose sum is σ = 1198110. Its totient is φ = 319488.

The previous prime is 638977. The next prime is 638993. The reversal of 638984 is 489836.

It can be written as a sum of positive squares in only one way, i.e., 624100 + 14884 = 790^2 + 122^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39929 + ... + 39944.

2⁶³⁸⁹⁸⁴ is an apocalyptic number.

It is an amenable number.

638984 is a deficient number, since it is larger than the sum of its proper divisors (559126).

638984 is a wasteful number, since it uses less digits than its factorization.

638984 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 79879 (or 79875 counting only the distinct ones).

The product of its digits is 41472, while the sum is 38.

The square root of 638984 is about 799.3647477841. The cubic root of 638984 is about 86.1317612479.

The spelling of 638984 in words is "six hundred thirty-eight thousand, nine hundred eighty-four".