12991813 has 2 divisors, whose sum is σ = 12991814. Its totient is φ = 12991812.

The previous prime is 12991807. The next prime is 12991871. The reversal of 12991813 is 31819921.

12991813 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12723489 + 268324 = 3567^2 + 518^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12991813 is a prime.

It is equal to p₈₄₈₇₃₄ and since 12991813 and 848734 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12991513) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6495906 + 6495907.

It is an arithmetic number, because the mean of its divisors is an integer number (6495907).

Almost surely, 2^12991813 is an apocalyptic number.

It is an amenable number.

12991813 is a deficient number, since it is larger than the sum of its proper divisors (1).

12991813 is an equidigital number, since it uses as much as digits as its factorization.

12991813 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3888, while the sum is 34.

The square root of 12991813 is about 3604.4157640317. The cubic root of 12991813 is about 235.0840984654.

The spelling of 12991813 in words is "twelve million, nine hundred ninety-one thousand, eight hundred thirteen".