491138685 has 24 divisors (see below), whose sum is σ = 851958744. Its totient is φ = 261740160.

The previous prime is 491138617. The next prime is 491138689. The reversal of 491138685 is 586831194.

491138685 is a `hidden beast` number, since 491 + 1 + 3 + 86 + 85 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 262342809 + 228795876 = 16197^2 + 15126^2 .

It is not a de Polignac number, because 491138685 - 2⁹ = 491138173 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 491138685.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (491138689) 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 23 ways as a sum of consecutive naturals, for example, 69579 + ... + 76311.

It is an arithmetic number, because the mean of its divisors is an integer number (35498281).

Almost surely, 2^491138685 is an apocalyptic number.

491138685 is a gapful number since it is divisible by the number (45) formed by its first and last digit.

It is an amenable number.

491138685 is a deficient number, since it is larger than the sum of its proper divisors (360820059).

491138685 is a wasteful number, since it uses less digits than its factorization.

491138685 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8365 (or 8362 counting only the distinct ones).

The product of its digits is 207360, while the sum is 45.

The square root of 491138685 is about 22161.6489684319. The cubic root of 491138685 is about 788.9837303338.

The spelling of 491138685 in words is "four hundred ninety-one million, one hundred thirty-eight thousand, six hundred eighty-five".