12186821 has 2 divisors, whose sum is σ = 12186822. Its totient is φ = 12186820.

The previous prime is 12186787. The next prime is 12186827. The reversal of 12186821 is 12868121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11356900 + 829921 = 3370^2 + 911^2 .

It is a cyclic number.

It is not a de Polignac number, because 12186821 - 2¹⁴ = 12170437 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12186827) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6093410 + 6093411.

It is an arithmetic number, because the mean of its divisors is an integer number (6093411).

Almost surely, 2^12186821 is an apocalyptic number.

It is an amenable number.

12186821 is a deficient number, since it is larger than the sum of its proper divisors (1).

12186821 is an equidigital number, since it uses as much as digits as its factorization.

12186821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1536, while the sum is 29.

The square root of 12186821 is about 3490.9627611878. The cubic root of 12186821 is about 230.1248282697.

The spelling of 12186821 in words is "twelve million, one hundred eighty-six thousand, eight hundred twenty-one".