1645616563 has 2 divisors, whose sum is σ = 1645616564. Its totient is φ = 1645616562.

The previous prime is 1645616561. The next prime is 1645616569. The reversal of 1645616563 is 3656165461.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1645616563 - 2¹ = 1645616561 is a prime.

Together with 1645616561, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (1645616561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 822808281 + 822808282.

It is an arithmetic number, because the mean of its divisors is an integer number (822808282).

Almost surely, 2^1645616563 is an apocalyptic number.

1645616563 is a deficient number, since it is larger than the sum of its proper divisors (1).

1645616563 is an equidigital number, since it uses as much as digits as its factorization.

1645616563 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 388800, while the sum is 43.

The square root of 1645616563 is about 40566.1997603917. The cubic root of 1645616563 is about 1180.6184068208.

The spelling of 1645616563 in words is "one billion, six hundred forty-five million, six hundred sixteen thousand, five hundred sixty-three".