1221133209 has 8 divisors (see below), whose sum is σ = 1639891680. Its totient is φ = 808231776.

The previous prime is 1221133159. The next prime is 1221133231. The reversal of 1221133209 is 9023311221.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1221133209 - 2²⁷ = 1086915481 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1221133259) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1463772 + ... + 1464605.

It is an arithmetic number, because the mean of its divisors is an integer number (204986460).

Almost surely, 2^1221133209 is an apocalyptic number.

It is an amenable number.

1221133209 is a deficient number, since it is larger than the sum of its proper divisors (418758471).

1221133209 is a wasteful number, since it uses less digits than its factorization.

1221133209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2928519.

The product of its (nonzero) digits is 648, while the sum is 24.

The square root of 1221133209 is about 34944.7164675863. The cubic root of 1221133209 is about 1068.8604658843.

The spelling of 1221133209 in words is "one billion, two hundred twenty-one million, one hundred thirty-three thousand, two hundred nine".