1213212109 has 2 divisors, whose sum is σ = 1213212110. Its totient is φ = 1213212108.

The previous prime is 1213212107. The next prime is 1213212137. The reversal of 1213212109 is 9012123121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1177176100 + 36036009 = 34310^2 + 6003^2 .

It is a cyclic number.

It is not a de Polignac number, because 1213212109 - 2¹ = 1213212107 is a prime.

Together with 1213212107, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 1213212109.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1213212107) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 606606054 + 606606055.

It is an arithmetic number, because the mean of its divisors is an integer number (606606055).

Almost surely, 2^1213212109 is an apocalyptic number.

It is an amenable number.

1213212109 is a deficient number, since it is larger than the sum of its proper divisors (1).

1213212109 is an equidigital number, since it uses as much as digits as its factorization.

1213212109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 216, while the sum is 22.

The square root of 1213212109 is about 34831.1944813841. The cubic root of 1213212109 is about 1066.5443321399.

The spelling of 1213212109 in words is "one billion, two hundred thirteen million, two hundred twelve thousand, one hundred nine".