1221098209 has 2 divisors, whose sum is σ = 1221098210. Its totient is φ = 1221098208.

The previous prime is 1221098173. The next prime is 1221098233. The reversal of 1221098209 is 9028901221.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1209091984 + 12006225 = 34772^2 + 3465^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221098209 - 2⁹ = 1221097697 is a prime.

It is not a weakly prime, because it can be changed into another prime (1221098009) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610549104 + 610549105.

It is an arithmetic number, because the mean of its divisors is an integer number (610549105).

Almost surely, 2^1221098209 is an apocalyptic number.

It is an amenable number.

1221098209 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221098209 is an equidigital number, since it uses as much as digits as its factorization.

1221098209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5184, while the sum is 34.

The square root of 1221098209 is about 34944.2156729837. The cubic root of 1221098209 is about 1068.8502539288.

The spelling of 1221098209 in words is "one billion, two hundred twenty-one million, ninety-eight thousand, two hundred nine".