21122312261 has 2 divisors, whose sum is σ = 21122312262. Its totient is φ = 21122312260.

The previous prime is 21122312249. The next prime is 21122312273. The reversal of 21122312261 is 16221322112.

It is a balanced prime because it is at equal distance from previous prime (21122312249) and next prime (21122312273).

It can be written as a sum of positive squares in only one way, i.e., 19180588036 + 1941724225 = 138494^2 + 44065^2 .

It is a cyclic number.

It is not a de Polignac number, because 21122312261 - 2¹⁰ = 21122311237 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21122312291) 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, 10561156130 + 10561156131.

It is an arithmetic number, because the mean of its divisors is an integer number (10561156131).

Almost surely, 2^21122312261 is an apocalyptic number.

It is an amenable number.

21122312261 is a deficient number, since it is larger than the sum of its proper divisors (1).

21122312261 is an equidigital number, since it uses as much as digits as its factorization.

21122312261 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 576, while the sum is 23.

Adding to 21122312261 its reverse (16221322112), we get a palindrome (37343634373).

The spelling of 21122312261 in words is "twenty-one billion, one hundred twenty-two million, three hundred twelve thousand, two hundred sixty-one".