1231216513 has 2 divisors, whose sum is σ = 1231216514. Its totient is φ = 1231216512.

The previous prime is 1231216471. The next prime is 1231216523. The reversal of 1231216513 is 3156121321.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1010159089 + 221057424 = 31783^2 + 14868^2 .

It is an emirp because it is prime and its reverse (3156121321) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1231216513 - 2²⁹ = 694345601 is a prime.

It is not a weakly prime, because it can be changed into another prime (1231216523) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 615608256 + 615608257.

It is an arithmetic number, because the mean of its divisors is an integer number (615608257).

Almost surely, 2^1231216513 is an apocalyptic number.

It is an amenable number.

1231216513 is a deficient number, since it is larger than the sum of its proper divisors (1).

1231216513 is an equidigital number, since it uses as much as digits as its factorization.

1231216513 is an odious number, because the sum of its binary digits is odd.

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

The square root of 1231216513 is about 35088.6949458084. The cubic root of 1231216513 is about 1071.7943842597.

Adding to 1231216513 its reverse (3156121321), we get a palindrome (4387337834).

The spelling of 1231216513 in words is "one billion, two hundred thirty-one million, two hundred sixteen thousand, five hundred thirteen".