12521666191 has 2 divisors, whose sum is σ = 12521666192. Its totient is φ = 12521666190.

The previous prime is 12521666189. The next prime is 12521666293. The reversal of 12521666191 is 19166612521.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 12521666191 - 2¹ = 12521666189 is a prime.

Together with 12521666189, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12521666491) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6260833095 + 6260833096.

It is an arithmetic number, because the mean of its divisors is an integer number (6260833096).

Almost surely, 2^12521666191 is an apocalyptic number.

12521666191 is a deficient number, since it is larger than the sum of its proper divisors (1).

12521666191 is an equidigital number, since it uses as much as digits as its factorization.

12521666191 is an evil number, because the sum of its binary digits is even.

The product of its digits is 38880, while the sum is 40.

The spelling of 12521666191 in words is "twelve billion, five hundred twenty-one million, six hundred sixty-six thousand, one hundred ninety-one".