1216100065 has 16 divisors (see below), whose sum is σ = 1530334800. Its totient is φ = 926456832.

The previous prime is 1216100033. The next prime is 1216100077. The reversal of 1216100065 is 5600016121.

It can be written as a sum of positive squares in 8 ways, for example, as 43681 + 1216056384 = 209^2 + 34872^2 .

It is a cyclic number.

It is not a de Polignac number, because 1216100065 - 2⁵ = 1216100033 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 46860 + ... + 68029.

It is an arithmetic number, because the mean of its divisors is an integer number (95645925).

Almost surely, 2^1216100065 is an apocalyptic number.

It is an amenable number.

1216100065 is a deficient number, since it is larger than the sum of its proper divisors (314234735).

1216100065 is a wasteful number, since it uses less digits than its factorization.

1216100065 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 114996.

The product of its (nonzero) digits is 360, while the sum is 22.

The square root of 1216100065 is about 34872.6262991476. The cubic root of 1216100065 is about 1067.3899364939.

Adding to 1216100065 its reverse (5600016121), we get a palindrome (6816116186).

The spelling of 1216100065 in words is "one billion, two hundred sixteen million, one hundred thousand, sixty-five".