643399693 has 2 divisors, whose sum is σ = 643399694. Its totient is φ = 643399692.

The previous prime is 643399643. The next prime is 643399703. The reversal of 643399693 is 396993346.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 589421284 + 53978409 = 24278^2 + 7347^2 .

It is a cyclic number.

It is not a de Polignac number, because 643399693 - 2⁹ = 643399181 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 643399693.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (643399613) 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, 321699846 + 321699847.

It is an arithmetic number, because the mean of its divisors is an integer number (321699847).

Almost surely, 2^643399693 is an apocalyptic number.

It is an amenable number.

643399693 is a deficient number, since it is larger than the sum of its proper divisors (1).

643399693 is an equidigital number, since it uses as much as digits as its factorization.

643399693 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2834352, while the sum is 52.

The square root of 643399693 is about 25365.3246184629. The cubic root of 643399693 is about 863.2971021635.

The spelling of 643399693 in words is "six hundred forty-three million, three hundred ninety-nine thousand, six hundred ninety-three".