491908005 has 128 divisors (see below), whose sum is σ = 1010880000. Its totient is φ = 225275904.

The previous prime is 491907991. The next prime is 491908009. The reversal of 491908005 is 500809194.

491908005 is a `hidden beast` number, since 491 + 90 + 80 + 0 + 5 = 666.

It is not a de Polignac number, because 491908005 - 2⁵ = 491907973 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (491908009) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 1264351 + ... + 1264739.

It is an arithmetic number, because the mean of its divisors is an integer number (7897500).

Almost surely, 2^491908005 is an apocalyptic number.

491908005 is a gapful number since it is divisible by the number (45) formed by its first and last digit.

It is an amenable number.

491908005 is an abundant number, since it is smaller than the sum of its proper divisors (518971995).

491908005 is a wasteful number, since it uses less digits than its factorization.

491908005 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 468 (or 462 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 36.

The square root of 491908005 is about 22178.9991884215. Note that the first 3 decimals coincide. The cubic root of 491908005 is about 789.3954703252.

Adding to 491908005 its sum of digits (36), we get a square (491908041 = 22179²).

The spelling of 491908005 in words is "four hundred ninety-one million, nine hundred eight thousand, five".