1221212089 has 2 divisors, whose sum is σ = 1221212090. Its totient is φ = 1221212088.

The previous prime is 1221212063. The next prime is 1221212143. The reversal of 1221212089 is 9802121221.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 990172089 + 231040000 = 31467^2 + 15200^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221212089 - 2⁹ = 1221211577 is a prime.

It is not a weakly prime, because it can be changed into another prime (1221212029) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610606044 + 610606045.

It is an arithmetic number, because the mean of its divisors is an integer number (610606045).

Almost surely, 2^1221212089 is an apocalyptic number.

It is an amenable number.

1221212089 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221212089 is an equidigital number, since it uses as much as digits as its factorization.

1221212089 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1152, while the sum is 28.

The square root of 1221212089 is about 34945.8450892234. The cubic root of 1221212089 is about 1068.8834799987.

The spelling of 1221212089 in words is "one billion, two hundred twenty-one million, two hundred twelve thousand, eighty-nine".