1216311405 has 16 divisors (see below), whose sum is σ = 1947625344. Its totient is φ = 648190400.

The previous prime is 1216311401. The next prime is 1216311419. The reversal of 1216311405 is 5041136121.

It is a happy number.

It is not a de Polignac number, because 1216311405 - 2² = 1216311401 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 (1216311401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11649 + ... + 50678.

It is an arithmetic number, because the mean of its divisors is an integer number (121726584).

Almost surely, 2^1216311405 is an apocalyptic number.

1216311405 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1216311405 is a deficient number, since it is larger than the sum of its proper divisors (731313939).

1216311405 is a wasteful number, since it uses less digits than its factorization.

1216311405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63636.

The product of its (nonzero) digits is 720, while the sum is 24.

The square root of 1216311405 is about 34875.6563379100. The cubic root of 1216311405 is about 1067.4517650472.

Adding to 1216311405 its reverse (5041136121), we get a palindrome (6257447526).

The spelling of 1216311405 in words is "one billion, two hundred sixteen million, three hundred eleven thousand, four hundred five".