12991523 has 2 divisors, whose sum is σ = 12991524. Its totient is φ = 12991522.

The previous prime is 12991513. The next prime is 12991541. The reversal of 12991523 is 32519921.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 12991523 - 2⁸ = 12991267 is a prime.

It is a super-3 number, since 3×12991523³ (a number of 22 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 12991523.

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

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6495761 + 6495762.

It is an arithmetic number, because the mean of its divisors is an integer number (6495762).

Almost surely, 2^12991523 is an apocalyptic number.

12991523 is a deficient number, since it is larger than the sum of its proper divisors (1).

12991523 is an equidigital number, since it uses as much as digits as its factorization.

12991523 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4860, while the sum is 32.

The square root of 12991523 is about 3604.3755353736. The cubic root of 12991523 is about 235.0823492896.

The spelling of 12991523 in words is "twelve million, nine hundred ninety-one thousand, five hundred twenty-three".