1211221993 has 2 divisors, whose sum is σ = 1211221994. Its totient is φ = 1211221992.

The previous prime is 1211221981. The next prime is 1211222003. The reversal of 1211221993 is 3991221121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1196260569 + 14961424 = 34587^2 + 3868^2 .

It is a cyclic number.

It is not a de Polignac number, because 1211221993 - 2⁵ = 1211221961 is a prime.

It is not a weakly prime, because it can be changed into another prime (1211221093) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 605610996 + 605610997.

It is an arithmetic number, because the mean of its divisors is an integer number (605610997).

Almost surely, 2^1211221993 is an apocalyptic number.

It is an amenable number.

1211221993 is a deficient number, since it is larger than the sum of its proper divisors (1).

1211221993 is an equidigital number, since it uses as much as digits as its factorization.

1211221993 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1944, while the sum is 31.

The square root of 1211221993 is about 34802.6147437229. The cubic root of 1211221993 is about 1065.9608374181.

The spelling of 1211221993 in words is "one billion, two hundred eleven million, two hundred twenty-one thousand, nine hundred ninety-three".