643507 has 2 divisors, whose sum is σ = 643508. Its totient is φ = 643506.

The previous prime is 643493. The next prime is 643523. The reversal of 643507 is 705346.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 643507 - 2¹⁵ = 610739 is a prime.

It is not a weakly prime, because it can be changed into another prime (643547) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321753 + 321754.

It is an arithmetic number, because the mean of its divisors is an integer number (321754).

2⁶⁴³⁵⁰⁷ is an apocalyptic number.

643507 is a deficient number, since it is larger than the sum of its proper divisors (1).

643507 is an equidigital number, since it uses as much as digits as its factorization.

643507 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2520, while the sum is 25.

The square root of 643507 is about 802.1888805013. The cubic root of 643507 is about 86.3345093417.

The spelling of 643507 in words is "six hundred forty-three thousand, five hundred seven".