12506661 has 6 divisors (see below), whose sum is σ = 18065190. Its totient is φ = 8337768.

The previous prime is 12506651. The next prime is 12506677. The reversal of 12506661 is 16660521.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 7128900 + 5377761 = 2670^2 + 2319^2 .

It is not a de Polignac number, because 12506661 - 2¹⁰ = 12505637 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12506651) 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, 694806 + ... + 694823.

It is an arithmetic number, because the mean of its divisors is an integer number (3010865).

Almost surely, 2^12506661 is an apocalyptic number.

It is an amenable number.

12506661 is a deficient number, since it is larger than the sum of its proper divisors (5558529).

12506661 is a wasteful number, since it uses less digits than its factorization.

12506661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1389635 (or 1389632 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 12506661 is about 3536.4757881258. The cubic root of 12506661 is about 232.1206578580.

The spelling of 12506661 in words is "twelve million, five hundred six thousand, six hundred sixty-one".