643403 has 2 divisors, whose sum is σ = 643404. Its totient is φ = 643402.

The previous prime is 643373. The next prime is 643421. The reversal of 643403 is 304346.

It is a happy number.

643403 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 643403 - 2¹² = 639307 is a prime.

It is a Sophie Germain prime.

It is a nialpdrome in base 15.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 643403.

It is not a weakly prime, because it can be changed into another prime (643453) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321701 + 321702.

It is an arithmetic number, because the mean of its divisors is an integer number (321702).

2⁶⁴³⁴⁰³ is an apocalyptic number.

643403 is a deficient number, since it is larger than the sum of its proper divisors (1).

643403 is an equidigital number, since it uses as much as digits as its factorization.

643403 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 864, while the sum is 20.

The square root of 643403 is about 802.1240552433. The cubic root of 643403 is about 86.3298581243.

Adding to 643403 its reverse (304346), we get a palindrome (947749).

The spelling of 643403 in words is "six hundred forty-three thousand, four hundred three".