643426313 has 2 divisors, whose sum is σ = 643426314. Its totient is φ = 643426312.

The previous prime is 643426291. The next prime is 643426321. The reversal of 643426313 is 313624346.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 627402304 + 16024009 = 25048^2 + 4003^2 .

It is a cyclic number.

It is not a de Polignac number, because 643426313 - 2¹⁶ = 643360777 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 643426313.

It is not a weakly prime, because it can be changed into another prime (643426613) 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 as a sum of consecutive naturals, namely, 321713156 + 321713157.

It is an arithmetic number, because the mean of its divisors is an integer number (321713157).

Almost surely, 2^643426313 is an apocalyptic number.

It is an amenable number.

643426313 is a deficient number, since it is larger than the sum of its proper divisors (1).

643426313 is an equidigital number, since it uses as much as digits as its factorization.

643426313 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 31104, while the sum is 32.

The square root of 643426313 is about 25365.8493451333. The cubic root of 643426313 is about 863.3090080089.

The spelling of 643426313 in words is "six hundred forty-three million, four hundred twenty-six thousand, three hundred thirteen".