199638 has 16 divisors (see below), whose sum is σ = 443760. Its totient is φ = 66528.

The previous prime is 199637. The next prime is 199657. The reversal of 199638 is 836991.

199638 is a `hidden beast` number, since 19 + 9 + 638 = 666.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (199637) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1795 + ... + 1902.

It is an arithmetic number, because the mean of its divisors is an integer number (27735).

2¹⁹⁹⁶³⁸ is an apocalyptic number.

199638 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

199638 is an abundant number, since it is smaller than the sum of its proper divisors (244122).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

199638 is a wasteful number, since it uses less digits than its factorization.

199638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3708 (or 3702 counting only the distinct ones).

The product of its digits is 11664, while the sum is 36.

The square root of 199638 is about 446.8086838905. The cubic root of 199638 is about 58.4450503080.

The spelling of 199638 in words is "one hundred ninety-nine thousand, six hundred thirty-eight".