491367791 has 4 divisors (see below), whose sum is σ = 512731632. Its totient is φ = 470003952.

The previous prime is 491367781. The next prime is 491367803. The reversal of 491367791 is 197763194.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 197763194 = 2 ⋅98881597.

It is a cyclic number.

It is not a de Polignac number, because 491367791 - 2¹⁴ = 491351407 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (491367781) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10681886 + ... + 10681931.

It is an arithmetic number, because the mean of its divisors is an integer number (128182908).

Almost surely, 2^491367791 is an apocalyptic number.

491367791 is a deficient number, since it is larger than the sum of its proper divisors (21363841).

491367791 is a wasteful number, since it uses less digits than its factorization.

491367791 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21363840.

The product of its digits is 285768, while the sum is 47.

The square root of 491367791 is about 22166.8173403400. The cubic root of 491367791 is about 789.1063927727.

The spelling of 491367791 in words is "four hundred ninety-one million, three hundred sixty-seven thousand, seven hundred ninety-one".