1221021122209 has 4 divisors (see below), whose sum is σ = 1395452711104. Its totient is φ = 1046589533316.

The previous prime is 1221021122207. The next prime is 1221021122213. The reversal of 1221021122209 is 9022211201221.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1221021122209 - 2¹ = 1221021122207 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221021122207) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 87215794437 + ... + 87215794450.

It is an arithmetic number, because the mean of its divisors is an integer number (348863177776).

Almost surely, 2^{1221021122209} is an apocalyptic number.

It is an amenable number.

1221021122209 is a deficient number, since it is larger than the sum of its proper divisors (174431588895).

1221021122209 is an equidigital number, since it uses as much as digits as its factorization.

1221021122209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 174431588894.

The product of its (nonzero) digits is 576, while the sum is 25.

The spelling of 1221021122209 in words is "one trillion, two hundred twenty-one billion, twenty-one million, one hundred twenty-two thousand, two hundred nine".