491894991 has 32 divisors (see below), whose sum is σ = 836236800. Its totient is φ = 279936000.

The previous prime is 491894969. The next prime is 491895023. The reversal of 491894991 is 199498194.

It is not a de Polignac number, because 491894991 - 2⁵ = 491894959 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (491894191) 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 31 ways as a sum of consecutive naturals, for example, 42255 + ... + 52623.

It is an arithmetic number, because the mean of its divisors is an integer number (26132400).

Almost surely, 2^491894991 is an apocalyptic number.

491894991 is a deficient number, since it is larger than the sum of its proper divisors (344341809).

491894991 is a wasteful number, since it uses less digits than its factorization.

491894991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10636 (or 10630 counting only the distinct ones).

The product of its digits is 839808, while the sum is 54.

The square root of 491894991 is about 22178.7058008352. The cubic root of 491894991 is about 789.3885088045.

The spelling of 491894991 in words is "four hundred ninety-one million, eight hundred ninety-four thousand, nine hundred ninety-one".