491578851 has 8 divisors (see below), whose sum is σ = 693993744. Its totient is φ = 308441600.

The previous prime is 491578837. The next prime is 491578877. The reversal of 491578851 is 158875194.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 491578851 - 2⁵ = 491578819 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 491578851.

It is not an unprimeable number, because it can be changed into a prime (491578891) 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 7 ways as a sum of consecutive naturals, for example, 4819350 + ... + 4819451.

It is an arithmetic number, because the mean of its divisors is an integer number (86749218).

Almost surely, 2^491578851 is an apocalyptic number.

491578851 is a deficient number, since it is larger than the sum of its proper divisors (202414893).

491578851 is a wasteful number, since it uses less digits than its factorization.

491578851 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9638821.

The product of its digits is 403200, while the sum is 48.

The square root of 491578851 is about 22171.5775487447. The cubic root of 491578851 is about 789.2193597177.

The spelling of 491578851 in words is "four hundred ninety-one million, five hundred seventy-eight thousand, eight hundred fifty-one".