643693 has 2 divisors, whose sum is σ = 643694. Its totient is φ = 643692.

The previous prime is 643691. The next prime is 643697. The reversal of 643693 is 396346.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 636804 + 6889 = 798^2 + 83^2 .

It is a cyclic number.

It is not a de Polignac number, because 643693 - 2¹ = 643691 is a prime.

Together with 643691, it forms a pair of twin primes.

It is a d-powerful number, because it can be written as 6 + 4⁸ + 6⁶ + 3³ + 9⁶ + 3³ .

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (643691) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321846 + 321847.

It is an arithmetic number, because the mean of its divisors is an integer number (321847).

2⁶⁴³⁶⁹³ is an apocalyptic number.

It is an amenable number.

643693 is a deficient number, since it is larger than the sum of its proper divisors (1).

643693 is an equidigital number, since it uses as much as digits as its factorization.

643693 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 11664, while the sum is 31.

The square root of 643693 is about 802.3048049214. The cubic root of 643693 is about 86.3428266155.

The spelling of 643693 in words is "six hundred forty-three thousand, six hundred ninety-three".