643499 has 4 divisors (see below), whose sum is σ = 651336. Its totient is φ = 635664.

The previous prime is 643493. The next prime is 643507. The reversal of 643499 is 994346.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 643499 - 2⁸ = 643243 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (643493) 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 in 3 ways as a sum of consecutive naturals, for example, 3794 + ... + 3959.

It is an arithmetic number, because the mean of its divisors is an integer number (162834).

2⁶⁴³⁴⁹⁹ is an apocalyptic number.

643499 is a deficient number, since it is larger than the sum of its proper divisors (7837).

643499 is an equidigital number, since it uses as much as digits as its factorization.

643499 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7836.

The product of its digits is 23328, while the sum is 35.

The square root of 643499 is about 802.1838941290. The cubic root of 643499 is about 86.3341515735.

The spelling of 643499 in words is "six hundred forty-three thousand, four hundred ninety-nine".