12811661 has 2 divisors, whose sum is σ = 12811662. Its totient is φ = 12811660.

The previous prime is 12811607. The next prime is 12811679. The reversal of 12811661 is 16611821.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11095561 + 1716100 = 3331^2 + 1310^2 .

It is a cyclic number.

It is not a de Polignac number, because 12811661 - 2⁶ = 12811597 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 12811661.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12811691) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6405830 + 6405831.

It is an arithmetic number, because the mean of its divisors is an integer number (6405831).

Almost surely, 2^12811661 is an apocalyptic number.

It is an amenable number.

12811661 is a deficient number, since it is larger than the sum of its proper divisors (1).

12811661 is an equidigital number, since it uses as much as digits as its factorization.

12811661 is an evil number, because the sum of its binary digits is even.

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

The square root of 12811661 is about 3579.3380672968. The cubic root of 12811661 is about 233.9924328524.

The spelling of 12811661 in words is "twelve million, eight hundred eleven thousand, six hundred sixty-one".