211221211120261 has 2 divisors, whose sum is σ = 211221211120262. Its totient is φ = 211221211120260.

The previous prime is 211221211120253. The next prime is 211221211120307. The reversal of 211221211120261 is 162021112122112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 151557790996161 + 59663420124100 = 12310881^2 + 7724210^2 .

It is a cyclic number.

It is not a de Polignac number, because 211221211120261 - 2³ = 211221211120253 is a prime.

It is a super-2 number, since 2×211221211120261² (a number of 29 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (211221211120861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105610605560130 + 105610605560131.

It is an arithmetic number, because the mean of its divisors is an integer number (105610605560131).

Almost surely, 2^{211221211120261} is an apocalyptic number.

It is an amenable number.

211221211120261 is a deficient number, since it is larger than the sum of its proper divisors (1).

211221211120261 is an equidigital number, since it uses as much as digits as its factorization.

211221211120261 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 384, while the sum is 25.

Adding to 211221211120261 its reverse (162021112122112), we get a palindrome (373242323242373).

The spelling of 211221211120261 in words is "two hundred eleven trillion, two hundred twenty-one billion, two hundred eleven million, one hundred twenty thousand, two hundred sixty-one".