1645608889 has 2 divisors, whose sum is σ = 1645608890. Its totient is φ = 1645608888.

The previous prime is 1645608863. The next prime is 1645608893. The reversal of 1645608889 is 9888065461.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1420008489 + 225600400 = 37683^2 + 15020^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1645608889 is a prime.

It is not a weakly prime, because it can be changed into another prime (1645608089) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 822804444 + 822804445.

It is an arithmetic number, because the mean of its divisors is an integer number (822804445).

Almost surely, 2^1645608889 is an apocalyptic number.

It is an amenable number.

1645608889 is a deficient number, since it is larger than the sum of its proper divisors (1).

1645608889 is an equidigital number, since it uses as much as digits as its factorization.

1645608889 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3317760, while the sum is 55.

The square root of 1645608889 is about 40566.1051741475. The cubic root of 1645608889 is about 1180.6165716263.

The spelling of 1645608889 in words is "one billion, six hundred forty-five million, six hundred eight thousand, eight hundred eighty-nine".