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12661 = 111151

12661 has 4 divisors (see below), whose sum is σ = 13824. Its totient is φ = 11500.

The previous prime is 12659. The next prime is 12671. The reversal of 12661 is 16621.

It can be divided in two parts, 1 and 2661, that added together give a palindrome (2662).

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: 16621 = 111511.

It is a cyclic number.

It is not a de Polignac number, because 12661 - 21 = 12659 is a prime.

It is a Duffinian number.

It is a plaindrome in base 13.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12601) 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, 565 + ... + 586.

It is an arithmetic number, because the mean of its divisors is an integer number (3456).

212661 is an apocalyptic number.

12661 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

12661 is a deficient number, since it is larger than the sum of its proper divisors (1163).

12661 is a wasteful number, since it uses less digits than its factorization.

12661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1162.

The product of its digits is 72, while the sum is 16.

The square root of 12661 is about 112.5211091307. The cubic root of 12661 is about 23.3071588580.

The spelling of 12661 in words is "twelve thousand, six hundred sixty-one".

Divisors: 1 11 1151 12661