1211221129 has 2 divisors, whose sum is σ = 1211221130. Its totient is φ = 1211221128.

The previous prime is 1211221111. The next prime is 1211221157. The reversal of 1211221129 is 9211221121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 820249600 + 390971529 = 28640^2 + 19773^2 .

It is a cyclic number.

It is not a de Polignac number, because 1211221129 - 2⁵ = 1211221097 is a prime.

It is not a weakly prime, because it can be changed into another prime (1211221199) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 605610564 + 605610565.

It is an arithmetic number, because the mean of its divisors is an integer number (605610565).

Almost surely, 2^1211221129 is an apocalyptic number.

It is an amenable number.

1211221129 is a deficient number, since it is larger than the sum of its proper divisors (1).

1211221129 is an equidigital number, since it uses as much as digits as its factorization.

1211221129 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 144, while the sum is 22.

The square root of 1211221129 is about 34802.6023308603. The cubic root of 1211221129 is about 1065.9605839577.

The spelling of 1211221129 in words is "one billion, two hundred eleven million, two hundred twenty-one thousand, one hundred twenty-nine".