1221430289 has 2 divisors, whose sum is σ = 1221430290. Its totient is φ = 1221430288.

The previous prime is 1221430201. The next prime is 1221430291. The reversal of 1221430289 is 9820341221.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 901020289 + 320410000 = 30017^2 + 17900^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221430289 is a prime.

Together with 1221430291, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1221430489) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610715144 + 610715145.

It is an arithmetic number, because the mean of its divisors is an integer number (610715145).

Almost surely, 2^1221430289 is an apocalyptic number.

It is an amenable number.

1221430289 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221430289 is an equidigital number, since it uses as much as digits as its factorization.

1221430289 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6912, while the sum is 32.

The square root of 1221430289 is about 34948.9669232153. The cubic root of 1221430289 is about 1068.9471371057.

The spelling of 1221430289 in words is "one billion, two hundred twenty-one million, four hundred thirty thousand, two hundred eighty-nine".