1213864189 has 2 divisors, whose sum is σ = 1213864190. Its totient is φ = 1213864188.

The previous prime is 1213864187. The next prime is 1213864237. The reversal of 1213864189 is 9814683121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 768232089 + 445632100 = 27717^2 + 21110^2 .

It is a cyclic number.

It is not a de Polignac number, because 1213864189 - 2¹ = 1213864187 is a prime.

Together with 1213864187, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1213864181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 606932094 + 606932095.

It is an arithmetic number, because the mean of its divisors is an integer number (606932095).

Almost surely, 2^1213864189 is an apocalyptic number.

It is an amenable number.

1213864189 is a deficient number, since it is larger than the sum of its proper divisors (1).

1213864189 is an equidigital number, since it uses as much as digits as its factorization.

1213864189 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 82944, while the sum is 43.

The square root of 1213864189 is about 34840.5537986984. The cubic root of 1213864189 is about 1066.7353808056.

The spelling of 1213864189 in words is "one billion, two hundred thirteen million, eight hundred sixty-four thousand, one hundred eighty-nine".