12681521 has 6 divisors (see below), whose sum is σ = 12833622. Its totient is φ = 12531200.

The previous prime is 12681509. The next prime is 12681527. The reversal of 12681521 is 12518621.

It can be written as a sum of positive squares in 3 ways, for example, as 2190400 + 10491121 = 1480^2 + 3239^2 .

It is not a de Polignac number, because 12681521 - 2⁶ = 12681457 is a prime.

It is not an unprimeable number, because it can be changed into a prime (12681527) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 7121 + ... + 8721.

It is an arithmetic number, because the mean of its divisors is an integer number (2138937).

Almost surely, 2^12681521 is an apocalyptic number.

It is an amenable number.

12681521 is a deficient number, since it is larger than the sum of its proper divisors (152101).

12681521 is an frugal number, since it uses more digits than its factorization.

12681521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1779 (or 1690 counting only the distinct ones).

The product of its digits is 960, while the sum is 26.

The square root of 12681521 is about 3561.1123262262. The cubic root of 12681521 is about 233.1974417348.

The spelling of 12681521 in words is "twelve million, six hundred eighty-one thousand, five hundred twenty-one".