12105421 has 2 divisors, whose sum is σ = 12105422. Its totient is φ = 12105420.

The previous prime is 12105419. The next prime is 12105427. The reversal of 12105421 is 12450121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10176100 + 1929321 = 3190^2 + 1389^2 .

It is a cyclic number.

It is not a de Polignac number, because 12105421 - 2¹ = 12105419 is a prime.

Together with 12105419, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 12105395 and 12105404.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12105427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6052710 + 6052711.

It is an arithmetic number, because the mean of its divisors is an integer number (6052711).

Almost surely, 2^12105421 is an apocalyptic number.

It is an amenable number.

12105421 is a deficient number, since it is larger than the sum of its proper divisors (1).

12105421 is an equidigital number, since it uses as much as digits as its factorization.

12105421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 80, while the sum is 16.

The square root of 12105421 is about 3479.2845528930. The cubic root of 12105421 is about 229.6113221177.

Adding to 12105421 its reverse (12450121), we get a palindrome (24555542).

The spelling of 12105421 in words is "twelve million, one hundred five thousand, four hundred twenty-one".