491784779 has 4 divisors (see below), whose sum is σ = 494532360. Its totient is φ = 489037200.

The previous prime is 491784763. The next prime is 491784793. The reversal of 491784779 is 977487194.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 491784779 - 2⁴ = 491784763 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (491784739) 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, 1373522 + ... + 1373879.

It is an arithmetic number, because the mean of its divisors is an integer number (123633090).

Almost surely, 2^491784779 is an apocalyptic number.

491784779 is a deficient number, since it is larger than the sum of its proper divisors (2747581).

491784779 is a wasteful number, since it uses less digits than its factorization.

491784779 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2747580.

The product of its digits is 3556224, while the sum is 56.

The square root of 491784779 is about 22176.2210261352. The cubic root of 491784779 is about 789.3295486698.

The spelling of 491784779 in words is "four hundred ninety-one million, seven hundred eighty-four thousand, seven hundred seventy-nine".