1221120209 has 4 divisors (see below), whose sum is σ = 1274212416. Its totient is φ = 1168028004.

The previous prime is 1221120193. The next prime is 1221120211. The reversal of 1221120209 is 9020211221.

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 1221120209 - 2⁴ = 1221120193 is a prime.

It is a super-2 number, since 2×1221120209² = 2982269129656407362, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221120259) 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, 26546069 + ... + 26546114.

It is an arithmetic number, because the mean of its divisors is an integer number (318553104).

Almost surely, 2^1221120209 is an apocalyptic number.

It is an amenable number.

1221120209 is a deficient number, since it is larger than the sum of its proper divisors (53092207).

1221120209 is an equidigital number, since it uses as much as digits as its factorization.

1221120209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53092206.

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

The square root of 1221120209 is about 34944.5304590003. The cubic root of 1221120209 is about 1068.8566728950.

The spelling of 1221120209 in words is "one billion, two hundred twenty-one million, one hundred twenty thousand, two hundred nine".