643369 has 2 divisors, whose sum is σ = 643370. Its totient is φ = 643368.

The previous prime is 643303. The next prime is 643373. The reversal of 643369 is 963346.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 608400 + 34969 = 780^2 + 187^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-643369 is a prime.

It is a super-2 number, since 2×643369² = 827847340322, which contains 22 as substring.

It is a Chen prime.

It is a nialpdrome in base 15.

It is a self number, because there is not a number n which added to its sum of digits gives 643369.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 643369.

It is not a weakly prime, because it can be changed into another prime (643469) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321684 + 321685.

It is an arithmetic number, because the mean of its divisors is an integer number (321685).

2⁶⁴³³⁶⁹ is an apocalyptic number.

It is an amenable number.

643369 is a deficient number, since it is larger than the sum of its proper divisors (1).

643369 is an equidigital number, since it uses as much as digits as its factorization.

643369 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 643369 is about 802.1028612341. The cubic root of 643369 is about 86.3283374253.

The spelling of 643369 in words is "six hundred forty-three thousand, three hundred sixty-nine".