638181 has 12 divisors (see below), whose sum is σ = 962208. Its totient is φ = 406824.

The previous prime is 638179. The next prime is 638201. The reversal of 638181 is 181836.

It is not a de Polignac number, because 638181 - 2¹ = 638179 is a prime.

It is a super-2 number, since 2×638181² = 814549977522, which contains 22 as substring.

It is an alternating number because its digits alternate between even and odd.

638181 is a modest number, since divided by 8181 gives 63 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638161) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1335 + ... + 1748.

It is an arithmetic number, because the mean of its divisors is an integer number (80184).

2⁶³⁸¹⁸¹ is an apocalyptic number.

It is an amenable number.

638181 is a deficient number, since it is larger than the sum of its proper divisors (324027).

638181 is a wasteful number, since it uses less digits than its factorization.

638181 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3112 (or 3109 counting only the distinct ones).

The product of its digits is 1152, while the sum is 27.

The square root of 638181 is about 798.8623160470. The cubic root of 638181 is about 86.0956660317.

The spelling of 638181 in words is "six hundred thirty-eight thousand, one hundred eighty-one".