12591661 has 4 divisors (see below), whose sum is σ = 13254400. Its totient is φ = 11928924.

The previous prime is 12591659. The next prime is 12591671. The reversal of 12591661 is 16619521.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 16619521 = 223 ⋅74527.

It is a cyclic number.

It is not a de Polignac number, because 12591661 - 2¹ = 12591659 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12591671) 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, 331341 + ... + 331378.

It is an arithmetic number, because the mean of its divisors is an integer number (3313600).

Almost surely, 2^12591661 is an apocalyptic number.

It is an amenable number.

12591661 is a deficient number, since it is larger than the sum of its proper divisors (662739).

12591661 is an equidigital number, since it uses as much as digits as its factorization.

12591661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 662738.

The product of its digits is 3240, while the sum is 31.

The square root of 12591661 is about 3548.4730518915. The cubic root of 12591661 is about 232.6453309591.

The spelling of 12591661 in words is "twelve million, five hundred ninety-one thousand, six hundred sixty-one".