491778194987518 has 8 divisors (see below), whose sum is σ = 737668025570448. Its totient is φ = 245888853130704.

The previous prime is 491778194987507. The next prime is 491778194987557. The reversal of 491778194987518 is 815789491877194.

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 119655471 + ... + 123697162.

It is an arithmetic number, because the mean of its divisors is an integer number (92208503196306).

Almost surely, 2^{491778194987518} is an apocalyptic number.

491778194987518 is a deficient number, since it is larger than the sum of its proper divisors (245889830582930).

491778194987518 is a wasteful number, since it uses less digits than its factorization.

491778194987518 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 244363058.

The product of its digits is 10241925120, while the sum is 88.

The spelling of 491778194987518 in words is "four hundred ninety-one trillion, seven hundred seventy-eight billion, one hundred ninety-four million, nine hundred eighty-seven thousand, five hundred eighteen".