491221212111 has 24 divisors (see below), whose sum is σ = 810950890880. Its totient is φ = 280681901136.

The previous prime is 491221212103. The next prime is 491221212113. The reversal of 491221212111 is 111212122194.

491221212111 is a `hidden beast` number, since 491 + 22 + 121 + 21 + 11 = 666.

It is not a de Polignac number, because 491221212111 - 2³ = 491221212103 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 (491221212113) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 945756 + ... + 1369998.

Almost surely, 2^491221212111 is an apocalyptic number.

491221212111 is a deficient number, since it is larger than the sum of its proper divisors (319729678769).

491221212111 is a wasteful number, since it uses less digits than its factorization.

491221212111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 442635 (or 442632 counting only the distinct ones).

The product of its digits is 576, while the sum is 27.

The spelling of 491221212111 in words is "four hundred ninety-one billion, two hundred twenty-one million, two hundred twelve thousand, one hundred eleven".