643544467 has 2 divisors, whose sum is σ = 643544468. Its totient is φ = 643544466.

The previous prime is 643544453. The next prime is 643544491. The reversal of 643544467 is 764445346.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-643544467 is a prime.

It is not a weakly prime, because it can be changed into another prime (643544417) 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, 321772233 + 321772234.

It is an arithmetic number, because the mean of its divisors is an integer number (321772234).

Almost surely, 2^643544467 is an apocalyptic number.

643544467 is a deficient number, since it is larger than the sum of its proper divisors (1).

643544467 is an equidigital number, since it uses as much as digits as its factorization.

643544467 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 967680, while the sum is 43.

The square root of 643544467 is about 25368.1782357346. The cubic root of 643544467 is about 863.3618486463.

The spelling of 643544467 in words is "six hundred forty-three million, five hundred forty-four thousand, four hundred sixty-seven".