1221231111 has 8 divisors (see below), whose sum is σ = 1641129984. Its totient is φ = 807743160.

The previous prime is 1221231107. The next prime is 1221231113. The reversal of 1221231111 is 1111321221.

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

It is not a de Polignac number, because 1221231111 - 2² = 1221231107 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221231113) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1602285 + ... + 1603046.

It is an arithmetic number, because the mean of its divisors is an integer number (205141248).

Almost surely, 2^1221231111 is an apocalyptic number.

1221231111 is a deficient number, since it is larger than the sum of its proper divisors (419898873).

1221231111 is a wasteful number, since it uses less digits than its factorization.

1221231111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3205461.

The product of its digits is 24, while the sum is 15.

The square root of 1221231111 is about 34946.1172521355. The cubic root of 1221231111 is about 1068.8890297298.

Adding to 1221231111 its reverse (1111321221), we get a palindrome (2332552332).

The spelling of 1221231111 in words is "one billion, two hundred twenty-one million, two hundred thirty-one thousand, one hundred eleven".