491317640 has 32 divisors (see below), whose sum is σ = 1205962560. Its totient is φ = 178660800.

The previous prime is 491317639. The next prime is 491317643. The reversal of 491317640 is 46713194.

It is a self number, because there is not a number n which added to its sum of digits gives 491317640.

It is not an unprimeable number, because it can be changed into a prime (491317643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 557876 + ... + 558755.

It is an arithmetic number, because the mean of its divisors is an integer number (37686330).

Almost surely, 2^491317640 is an apocalyptic number.

491317640 is a gapful number since it is divisible by the number (40) formed by its first and last digit.

It is an amenable number.

491317640 is an abundant number, since it is smaller than the sum of its proper divisors (714644920).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

491317640 is a wasteful number, since it uses less digits than its factorization.

491317640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1116653 (or 1116649 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 35.

The square root of 491317640 is about 22165.6860935997. The cubic root of 491317640 is about 789.0795453874.

The spelling of 491317640 in words is "four hundred ninety-one million, three hundred seventeen thousand, six hundred forty".