1211122261 has 2 divisors, whose sum is σ = 1211122262. Its totient is φ = 1211122260.

The previous prime is 1211122207. The next prime is 1211122267. The reversal of 1211122261 is 1622211121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1089990225 + 121132036 = 33015^2 + 11006^2 .

It is a cyclic number.

It is not a de Polignac number, because 1211122261 - 2¹¹ = 1211120213 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1211122267) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 605561130 + 605561131.

It is an arithmetic number, because the mean of its divisors is an integer number (605561131).

Almost surely, 2^1211122261 is an apocalyptic number.

It is an amenable number.

1211122261 is a deficient number, since it is larger than the sum of its proper divisors (1).

1211122261 is an equidigital number, since it uses as much as digits as its factorization.

1211122261 is an evil number, because the sum of its binary digits is even.

The product of its digits is 96, while the sum is 19.

The square root of 1211122261 is about 34801.1818908496. The cubic root of 1211122261 is about 1065.9315795488.

Adding to 1211122261 its reverse (1622211121), we get a palindrome (2833333382).

The spelling of 1211122261 in words is "one billion, two hundred eleven million, one hundred twenty-two thousand, two hundred sixty-one".