21212201202251 has 2 divisors, whose sum is σ = 21212201202252. Its totient is φ = 21212201202250.

The previous prime is 21212201202209. The next prime is 21212201202263. The reversal of 21212201202251 is 15220210221212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21212201202251 - 2³⁰ = 21211127460427 is a prime.

It is not a weakly prime, because it can be changed into another prime (21212201202281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10606100601125 + 10606100601126.

It is an arithmetic number, because the mean of its divisors is an integer number (10606100601126).

Almost surely, 2^{21212201202251} is an apocalyptic number.

21212201202251 is a deficient number, since it is larger than the sum of its proper divisors (1).

21212201202251 is an equidigital number, since it uses as much as digits as its factorization.

21212201202251 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 640, while the sum is 23.

Adding to 21212201202251 its reverse (15220210221212), we get a palindrome (36432411423463).

The spelling of 21212201202251 in words is "twenty-one trillion, two hundred twelve billion, two hundred one million, two hundred two thousand, two hundred fifty-one".