491878861791 has 8 divisors (see below), whose sum is σ = 655894674864. Its totient is φ = 327891144960.

The previous prime is 491878861763. The next prime is 491878861811. The reversal of 491878861791 is 197168878194.

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

It is not a de Polignac number, because 491878861791 - 2¹⁷ = 491878730719 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (491878862791) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6983176 + ... + 7053261.

It is an arithmetic number, because the mean of its divisors is an integer number (81986834358).

Almost surely, 2^491878861791 is an apocalyptic number.

491878861791 is a deficient number, since it is larger than the sum of its proper divisors (164015813073).

491878861791 is a wasteful number, since it uses less digits than its factorization.

491878861791 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14048121.

The product of its digits is 48771072, while the sum is 69.

The spelling of 491878861791 in words is "four hundred ninety-one billion, eight hundred seventy-eight million, eight hundred sixty-one thousand, seven hundred ninety-one".