1213212009 has 4 divisors (see below), whose sum is σ = 1617616016. Its totient is φ = 808808004.

The previous prime is 1213211999. The next prime is 1213212023. The reversal of 1213212009 is 9002123121.

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 not a de Polignac number, because 1213212009 - 2⁵ = 1213211977 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1213212109) 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, 202201999 + ... + 202202004.

It is an arithmetic number, because the mean of its divisors is an integer number (404404004).

Almost surely, 2^1213212009 is an apocalyptic number.

It is an amenable number.

1213212009 is a deficient number, since it is larger than the sum of its proper divisors (404404007).

1213212009 is an equidigital number, since it uses as much as digits as its factorization.

1213212009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 404404006.

The product of its (nonzero) digits is 216, while the sum is 21.

The square root of 1213212009 is about 34831.1930458892. The cubic root of 1213212009 is about 1066.5443028363.

The spelling of 1213212009 in words is "one billion, two hundred thirteen million, two hundred twelve thousand, nine".