12991538 has 8 divisors (see below), whose sum is σ = 22271232. Its totient is φ = 5567796.

The previous prime is 12991523. The next prime is 12991541. The reversal of 12991538 is 83519921.

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

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 in 3 ways as a sum of consecutive naturals, for example, 463970 + ... + 463997.

It is an arithmetic number, because the mean of its divisors is an integer number (2783904).

Almost surely, 2^12991538 is an apocalyptic number.

12991538 is a deficient number, since it is larger than the sum of its proper divisors (9279694).

12991538 is an equidigital number, since it uses as much as digits as its factorization.

12991538 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 927976.

The product of its digits is 19440, while the sum is 38.

The square root of 12991538 is about 3604.3776161773. The cubic root of 12991538 is about 235.0824397648.

The spelling of 12991538 in words is "twelve million, nine hundred ninety-one thousand, five hundred thirty-eight".