491643 has 16 divisors (see below), whose sum is σ = 739200. Its totient is φ = 322920.

The previous prime is 491639. The next prime is 491651. The reversal of 491643 is 346194.

It is not a de Polignac number, because 491643 - 2² = 491639 is a prime.

It is a Smith number, since the sum of its digits (27) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (27).

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

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3468 + ... + 3606.

It is an arithmetic number, because the mean of its divisors is an integer number (46200).

2⁴⁹¹⁶⁴³ is an apocalyptic number.

491643 is a deficient number, since it is larger than the sum of its proper divisors (247557).

491643 is a wasteful number, since it uses less digits than its factorization.

491643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 279 (or 273 counting only the distinct ones).

The product of its digits is 2592, while the sum is 27.

The square root of 491643 is about 701.1725893102. The cubic root of 491643 is about 78.9253688175.

The spelling of 491643 in words is "four hundred ninety-one thousand, six hundred forty-three".