1984438661 has 2 divisors, whose sum is σ = 1984438662. Its totient is φ = 1984438660.

The previous prime is 1984438637. The next prime is 1984438699. The reversal of 1984438661 is 1668344891.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1548422500 + 436016161 = 39350^2 + 20881^2 .

It is a cyclic number.

It is not a de Polignac number, because 1984438661 - 2³⁰ = 910696837 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1984438861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 992219330 + 992219331.

It is an arithmetic number, because the mean of its divisors is an integer number (992219331).

Almost surely, 2^1984438661 is an apocalyptic number.

It is an amenable number.

1984438661 is a deficient number, since it is larger than the sum of its proper divisors (1).

1984438661 is an equidigital number, since it uses as much as digits as its factorization.

1984438661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 995328, while the sum is 50.

The square root of 1984438661 is about 44547.0387455777. The cubic root of 1984438661 is about 1256.6448617383.

The spelling of 1984438661 in words is "one billion, nine hundred eighty-four million, four hundred thirty-eight thousand, six hundred sixty-one".