638901 has 8 divisors (see below), whose sum is σ = 946560. Its totient is φ = 425916.

The previous prime is 638893. The next prime is 638923. The reversal of 638901 is 109836.

It is not a de Polignac number, because 638901 - 2³ = 638893 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 23663 = 638901 / (6 + 3 + 8 + 9 + 0 + 1).

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

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638971) 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, 11805 + ... + 11858.

It is an arithmetic number, because the mean of its divisors is an integer number (118320).

2⁶³⁸⁹⁰¹ is an apocalyptic number.

It is an amenable number.

638901 is a deficient number, since it is larger than the sum of its proper divisors (307659).

638901 is a wasteful number, since it uses less digits than its factorization.

638901 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23672 (or 23666 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 27.

The square root of 638901 is about 799.3128298733. The cubic root of 638901 is about 86.1280317618.

The spelling of 638901 in words is "six hundred thirty-eight thousand, nine hundred one".