1643630489 has 2 divisors, whose sum is σ = 1643630490. Its totient is φ = 1643630488.

The previous prime is 1643630441. The next prime is 1643630497. The reversal of 1643630489 is 9840363461.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1574740489 + 68890000 = 39683^2 + 8300^2 .

It is an emirp because it is prime and its reverse (9840363461) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1643630489 - 2¹⁶ = 1643564953 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (1643630789) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 821815244 + 821815245.

It is an arithmetic number, because the mean of its divisors is an integer number (821815245).

Almost surely, 2^1643630489 is an apocalyptic number.

It is an amenable number.

1643630489 is a deficient number, since it is larger than the sum of its proper divisors (1).

1643630489 is an equidigital number, since it uses as much as digits as its factorization.

1643630489 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 373248, while the sum is 44.

The square root of 1643630489 is about 40541.7129509842. The cubic root of 1643630489 is about 1180.1432577675.

The spelling of 1643630489 in words is "one billion, six hundred forty-three million, six hundred thirty thousand, four hundred eighty-nine".