491638 has 8 divisors (see below), whose sum is σ = 842832. Its totient is φ = 210696.

The previous prime is 491633. The next prime is 491639. The reversal of 491638 is 836194.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (491633) by changing a digit.

491638 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 17545 + ... + 17572.

It is an arithmetic number, because the mean of its divisors is an integer number (105354).

2⁴⁹¹⁶³⁸ is an apocalyptic number.

491638 is a deficient number, since it is larger than the sum of its proper divisors (351194).

491638 is a wasteful number, since it uses less digits than its factorization.

491638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35126.

The product of its digits is 5184, while the sum is 31.

The square root of 491638 is about 701.1690238452. The cubic root of 491638 is about 78.9251012601.

The spelling of 491638 in words is "four hundred ninety-one thousand, six hundred thirty-eight".