1216523113 has 4 divisors (see below), whose sum is σ = 1310101828. Its totient is φ = 1122944400.

The previous prime is 1216523071. The next prime is 1216523123. The reversal of 1216523113 is 3113256121.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 3113256121 = 17 ⋅183132713.

It can be written as a sum of positive squares in 2 ways, for example, as 600838144 + 615684969 = 24512^2 + 24813^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1216523113 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1216523123) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 46789338 + ... + 46789363.

It is an arithmetic number, because the mean of its divisors is an integer number (327525457).

Almost surely, 2^1216523113 is an apocalyptic number.

1216523113 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

It is an amenable number.

1216523113 is a deficient number, since it is larger than the sum of its proper divisors (93578715).

1216523113 is an equidigital number, since it uses as much as digits as its factorization.

1216523113 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 93578714.

The product of its digits is 1080, while the sum is 25.

The square root of 1216523113 is about 34878.6913888695. The cubic root of 1216523113 is about 1067.5136940803.

Adding to 1216523113 its reverse (3113256121), we get a palindrome (4329779234).

The spelling of 1216523113 in words is "one billion, two hundred sixteen million, five hundred twenty-three thousand, one hundred thirteen".