1221804889 has 2 divisors, whose sum is σ = 1221804890. Its totient is φ = 1221804888.

The previous prime is 1221804851. The next prime is 1221804931. The reversal of 1221804889 is 9884081221.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1211596864 + 10208025 = 34808^2 + 3195^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221804889 - 2⁷ = 1221804761 is a prime.

It is not a weakly prime, because it can be changed into another prime (1221804839) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610902444 + 610902445.

It is an arithmetic number, because the mean of its divisors is an integer number (610902445).

Almost surely, 2^1221804889 is an apocalyptic number.

It is an amenable number.

1221804889 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221804889 is an equidigital number, since it uses as much as digits as its factorization.

1221804889 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 73728, while the sum is 43.

The square root of 1221804889 is about 34954.3257551909. The cubic root of 1221804889 is about 1069.0564042691.

The spelling of 1221804889 in words is "one billion, two hundred twenty-one million, eight hundred four thousand, eight hundred eighty-nine".