1643144465 has 8 divisors (see below), whose sum is σ = 1972385640. Its totient is φ = 1314107392.

The previous prime is 1643144441. The next prime is 1643144467. The reversal of 1643144465 is 5644413461.

It can be written as a sum of positive squares in 4 ways, for example, as 560931856 + 1082212609 = 23684^2 + 32897^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1643144465 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1643144467) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 32714 + ... + 66003.

It is an arithmetic number, because the mean of its divisors is an integer number (246548205).

Almost surely, 2^1643144465 is an apocalyptic number.

It is an amenable number.

1643144465 is a deficient number, since it is larger than the sum of its proper divisors (329241175).

1643144465 is an equidigital number, since it uses as much as digits as its factorization.

1643144465 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 102051.

The product of its digits is 138240, while the sum is 38.

The square root of 1643144465 is about 40535.7183851477. The cubic root of 1643144465 is about 1180.0269229230.

The spelling of 1643144465 in words is "one billion, six hundred forty-three million, one hundred forty-four thousand, four hundred sixty-five".