21221201222251 has 2 divisors, whose sum is σ = 21221201222252. Its totient is φ = 21221201222250.

The previous prime is 21221201222203. The next prime is 21221201222279. The reversal of 21221201222251 is 15222210212212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21221201222251 - 2⁹ = 21221201221739 is a prime.

It is not a weakly prime, because it can be changed into another prime (21221201222201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610600611125 + 10610600611126.

It is an arithmetic number, because the mean of its divisors is an integer number (10610600611126).

Almost surely, 2^{21221201222251} is an apocalyptic number.

21221201222251 is a deficient number, since it is larger than the sum of its proper divisors (1).

21221201222251 is an equidigital number, since it uses as much as digits as its factorization.

21221201222251 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1280, while the sum is 25.

Adding to 21221201222251 its reverse (15222210212212), we get a palindrome (36443411434463).

The spelling of 21221201222251 in words is "twenty-one trillion, two hundred twenty-one billion, two hundred one million, two hundred twenty-two thousand, two hundred fifty-one".