1216311789 has 16 divisors (see below), whose sum is σ = 2021921280. Its totient is φ = 631850160.

The previous prime is 1216311779. The next prime is 1216311793. The reversal of 1216311789 is 9871136121.

It is not a de Polignac number, because 1216311789 - 2⁷ = 1216311661 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1216311749) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2632479 + ... + 2632940.

It is an arithmetic number, because the mean of its divisors is an integer number (126370080).

Almost surely, 2^1216311789 is an apocalyptic number.

It is an amenable number.

1216311789 is a deficient number, since it is larger than the sum of its proper divisors (805609491).

1216311789 is a wasteful number, since it uses less digits than its factorization.

1216311789 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5265440.

The product of its digits is 18144, while the sum is 39.

The square root of 1216311789 is about 34875.6618431823. The cubic root of 1216311789 is about 1067.4518773817.

The spelling of 1216311789 in words is "one billion, two hundred sixteen million, three hundred eleven thousand, seven hundred eighty-nine".