1216520105 has 4 divisors (see below), whose sum is σ = 1459824132. Its totient is φ = 973216080.

The previous prime is 1216520069. The next prime is 1216520111. The reversal of 1216520105 is 5010256121.

It is a happy number.

1216520105 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 273968704 + 942551401 = 16552^2 + 30701^2 .

It is not a de Polignac number, because 1216520105 - 2¹⁴ = 1216503721 is a prime.

It is a super-2 number, since 2×1216520105² = 2959842331738422050, which contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 121652006 + ... + 121652015.

It is an arithmetic number, because the mean of its divisors is an integer number (364956033).

Almost surely, 2^1216520105 is an apocalyptic number.

It is an amenable number.

1216520105 is a deficient number, since it is larger than the sum of its proper divisors (243304027).

1216520105 is an equidigital number, since it uses as much as digits as its factorization.

1216520105 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 243304026.

The product of its (nonzero) digits is 600, while the sum is 23.

The square root of 1216520105 is about 34878.6482679590. The cubic root of 1216520105 is about 1067.5128142275.

Adding to 1216520105 its reverse (5010256121), we get a palindrome (6226776226).

The spelling of 1216520105 in words is "one billion, two hundred sixteen million, five hundred twenty thousand, one hundred five".