1213229891 has 2 divisors, whose sum is σ = 1213229892. Its totient is φ = 1213229890.

The previous prime is 1213229867. The next prime is 1213229957. The reversal of 1213229891 is 1989223121.

It is a weak prime.

It is an emirp because it is prime and its reverse (1989223121) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1213229891 - 2¹⁸ = 1212967747 is a prime.

It is not a weakly prime, because it can be changed into another prime (1213229861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 606614945 + 606614946.

It is an arithmetic number, because the mean of its divisors is an integer number (606614946).

Almost surely, 2^1213229891 is an apocalyptic number.

1213229891 is a deficient number, since it is larger than the sum of its proper divisors (1).

1213229891 is an equidigital number, since it uses as much as digits as its factorization.

1213229891 is an evil number, because the sum of its binary digits is even.

The product of its digits is 15552, while the sum is 38.

The square root of 1213229891 is about 34831.4497401415. The cubic root of 1213229891 is about 1066.5495428799.

The spelling of 1213229891 in words is "one billion, two hundred thirteen million, two hundred twenty-nine thousand, eight hundred ninety-one".