491731985 has 16 divisors (see below), whose sum is σ = 595296000. Its totient is φ = 389923776.

The previous prime is 491731969. The next prime is 491732023. The reversal of 491731985 is 589137194.

It is a cyclic number.

It is not a de Polignac number, because 491731985 - 2⁴ = 491731969 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 314636 + ... + 316194.

It is an arithmetic number, because the mean of its divisors is an integer number (37206000).

Almost surely, 2^491731985 is an apocalyptic number.

It is an amenable number.

491731985 is a deficient number, since it is larger than the sum of its proper divisors (103564015).

491731985 is a wasteful number, since it uses less digits than its factorization.

491731985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2080.

The product of its digits is 272160, while the sum is 47.

The square root of 491731985 is about 22175.0306651423. The cubic root of 491731985 is about 789.3013023331.

The spelling of 491731985 in words is "four hundred ninety-one million, seven hundred thirty-one thousand, nine hundred eighty-five".