643223437 has 2 divisors, whose sum is σ = 643223438. Its totient is φ = 643223436.

The previous prime is 643223417. The next prime is 643223489. The reversal of 643223437 is 734322346.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 358761481 + 284461956 = 18941^2 + 16866^2 .

It is a cyclic number.

It is not a de Polignac number, because 643223437 - 2¹¹ = 643221389 is a prime.

It is equal to p_33459433 and since 643223437 and 33459433 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (643223417) 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, 321611718 + 321611719.

It is an arithmetic number, because the mean of its divisors is an integer number (321611719).

Almost surely, 2^643223437 is an apocalyptic number.

It is an amenable number.

643223437 is a deficient number, since it is larger than the sum of its proper divisors (1).

643223437 is an equidigital number, since it uses as much as digits as its factorization.

643223437 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 72576, while the sum is 34.

The square root of 643223437 is about 25361.8500310999. The cubic root of 643223437 is about 863.2182630466.

The spelling of 643223437 in words is "six hundred forty-three million, two hundred twenty-three thousand, four hundred thirty-seven".