638996 has 12 divisors (see below), whose sum is σ = 1184148. Its totient is φ = 300672.

The previous prime is 638993. The next prime is 638999. The reversal of 638996 is 699836.

It is an interprime number because it is at equal distance from previous prime (638993) and next prime (638999).

It can be written as a sum of positive squares in 2 ways, for example, as 190096 + 448900 = 436^2 + 670^2 .

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 638996.

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

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4631 + ... + 4766.

It is an arithmetic number, because the mean of its divisors is an integer number (98679).

2⁶³⁸⁹⁹⁶ is an apocalyptic number.

It is an amenable number.

638996 is a deficient number, since it is larger than the sum of its proper divisors (545152).

638996 is a wasteful number, since it uses less digits than its factorization.

638996 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9418 (or 9416 counting only the distinct ones).

The product of its digits is 69984, while the sum is 41.

The square root of 638996 is about 799.3722537091. The cubic root of 638996 is about 86.1323004239.

The spelling of 638996 in words is "six hundred thirty-eight thousand, nine hundred ninety-six".