21202120202251 has 2 divisors, whose sum is σ = 21202120202252. Its totient is φ = 21202120202250.

The previous prime is 21202120202189. The next prime is 21202120202261. The reversal of 21202120202251 is 15220202120212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21202120202251 - 2²⁷ = 21201985984523 is a prime.

It is not a weakly prime, because it can be changed into another prime (21202120202261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10601060101125 + 10601060101126.

It is an arithmetic number, because the mean of its divisors is an integer number (10601060101126).

Almost surely, 2^{21202120202251} is an apocalyptic number.

21202120202251 is a deficient number, since it is larger than the sum of its proper divisors (1).

21202120202251 is an equidigital number, since it uses as much as digits as its factorization.

21202120202251 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 22.

Adding to 21202120202251 its reverse (15220202120212), we get a palindrome (36422322322463).

The spelling of 21202120202251 in words is "twenty-one trillion, two hundred two billion, one hundred twenty million, two hundred two thousand, two hundred fifty-one".