1220808909 has 4 divisors (see below), whose sum is σ = 1627745216. Its totient is φ = 813872604.

The previous prime is 1220808871. The next prime is 1220808931. The reversal of 1220808909 is 9098080221.

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, and also an emirpimes, since its reverse is a distinct semiprime: 9098080221 = 3 ⋅3032693407.

It is not a de Polignac number, because 1220808909 - 2¹¹ = 1220806861 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1220808959) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 203468149 + ... + 203468154.

It is an arithmetic number, because the mean of its divisors is an integer number (406936304).

Almost surely, 2^1220808909 is an apocalyptic number.

It is an amenable number.

1220808909 is a deficient number, since it is larger than the sum of its proper divisors (406936307).

1220808909 is an equidigital number, since it uses as much as digits as its factorization.

1220808909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 406936306.

The product of its (nonzero) digits is 20736, while the sum is 39.

The square root of 1220808909 is about 34940.0759730141. The cubic root of 1220808909 is about 1068.7658373495.

The spelling of 1220808909 in words is "one billion, two hundred twenty million, eight hundred eight thousand, nine hundred nine".