12991040 has 28 divisors (see below), whose sum is σ = 30935676. Its totient is φ = 5196288.

The previous prime is 12991037. The next prime is 12991049. The reversal of 12991040 is 4019921.

It can be written as a sum of positive squares in 2 ways, for example, as 9634816 + 3356224 = 3104^2 + 1832^2 .

It is not an unprimeable number, because it can be changed into a prime (12991049) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19979 + ... + 20618.

Almost surely, 2^12991040 is an apocalyptic number.

12991040 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

12991040 is an abundant number, since it is smaller than the sum of its proper divisors (17944636).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

12991040 is an equidigital number, since it uses as much as digits as its factorization.

12991040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40614 (or 40604 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 26.

The square root of 12991040 is about 3604.3085328534. The cubic root of 12991040 is about 235.0794359493.

The spelling of 12991040 in words is "twelve million, nine hundred ninety-one thousand, forty".