12491081 has 4 divisors (see below), whose sum is σ = 12500100. Its totient is φ = 12482064.

The previous prime is 12491071. The next prime is 12491131. The reversal of 12491081 is 18019421.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 18019421 = 7 ⋅2574203.

It can be written as a sum of positive squares in 2 ways, for example, as 3841600 + 8649481 = 1960^2 + 2941^2 .

It is a cyclic number.

It is not a de Polignac number, because 12491081 - 2¹⁰ = 12490057 is a prime.

It is a super-3 number, since 3×12491081³ (a number of 22 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 12491081.

It is not an unprimeable number, because it can be changed into a prime (12491071) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1946 + ... + 5363.

It is an arithmetic number, because the mean of its divisors is an integer number (3125025).

Almost surely, 2^12491081 is an apocalyptic number.

It is an amenable number.

12491081 is a deficient number, since it is larger than the sum of its proper divisors (9019).

12491081 is an equidigital number, since it uses as much as digits as its factorization.

12491081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9018.

The product of its (nonzero) digits is 576, while the sum is 26.

The square root of 12491081 is about 3534.2723437788. The cubic root of 12491081 is about 232.0242307728.

The spelling of 12491081 in words is "twelve million, four hundred ninety-one thousand, eighty-one".