1643664313 has 2 divisors, whose sum is σ = 1643664314. Its totient is φ = 1643664312.

The previous prime is 1643664311. The next prime is 1643664367. The reversal of 1643664313 is 3134663461.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1416167424 + 227496889 = 37632^2 + 15083^2 .

It is an emirp because it is prime and its reverse (3134663461) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1643664313 - 2¹ = 1643664311 is a prime.

Together with 1643664311, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (1643664311) 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, 821832156 + 821832157.

It is an arithmetic number, because the mean of its divisors is an integer number (821832157).

Almost surely, 2^1643664313 is an apocalyptic number.

It is an amenable number.

1643664313 is a deficient number, since it is larger than the sum of its proper divisors (1).

1643664313 is an equidigital number, since it uses as much as digits as its factorization.

1643664313 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 93312, while the sum is 37.

The square root of 1643664313 is about 40542.1300994410. The cubic root of 1643664313 is about 1180.1513530363.

The spelling of 1643664313 in words is "one billion, six hundred forty-three million, six hundred sixty-four thousand, three hundred thirteen".