12421891 has 2 divisors, whose sum is σ = 12421892. Its totient is φ = 12421890.

The previous prime is 12421873. The next prime is 12421921. The reversal of 12421891 is 19812421.

12421891 is digitally balanced in base 2 and base 3, because in such bases it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 12421891 - 2⁵ = 12421859 is a prime.

It is not a weakly prime, because it can be changed into another prime (12421841) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6210945 + 6210946.

It is an arithmetic number, because the mean of its divisors is an integer number (6210946).

Almost surely, 2^12421891 is an apocalyptic number.

12421891 is a deficient number, since it is larger than the sum of its proper divisors (1).

12421891 is an equidigital number, since it uses as much as digits as its factorization.

12421891 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1152, while the sum is 28.

The square root of 12421891 is about 3524.4703148133. The cubic root of 12421891 is about 231.5950314777.

The spelling of 12421891 in words is "twelve million, four hundred twenty-one thousand, eight hundred ninety-one".