1221000221009 has 2 divisors, whose sum is σ = 1221000221010. Its totient is φ = 1221000221008.

The previous prime is 1221000220969. The next prime is 1221000221107. The reversal of 1221000221009 is 9001220001221.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1150760380225 + 70239840784 = 1072735^2 + 265028^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221000221009 - 2¹² = 1221000216913 is a prime.

It is not a weakly prime, because it can be changed into another prime (1221000221809) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610500110504 + 610500110505.

It is an arithmetic number, because the mean of its divisors is an integer number (610500110505).

Almost surely, 2^{1221000221009} is an apocalyptic number.

It is an amenable number.

1221000221009 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221000221009 is an equidigital number, since it uses as much as digits as its factorization.

1221000221009 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 144, while the sum is 20.

The spelling of 1221000221009 in words is "one trillion, two hundred twenty-one billion, two hundred twenty-one thousand, nine".