1645864573 has 2 divisors, whose sum is σ = 1645864574. Its totient is φ = 1645864572.

The previous prime is 1645864547. The next prime is 1645864601. The reversal of 1645864573 is 3754685461.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1246584249 + 399280324 = 35307^2 + 19982^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1645864573 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1645834573) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 822932286 + 822932287.

It is an arithmetic number, because the mean of its divisors is an integer number (822932287).

Almost surely, 2^1645864573 is an apocalyptic number.

It is an amenable number.

1645864573 is a deficient number, since it is larger than the sum of its proper divisors (1).

1645864573 is an equidigital number, since it uses as much as digits as its factorization.

1645864573 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2419200, while the sum is 49.

The square root of 1645864573 is about 40569.2565004586. The cubic root of 1645864573 is about 1180.6777139663.

The spelling of 1645864573 in words is "one billion, six hundred forty-five million, eight hundred sixty-four thousand, five hundred seventy-three".