643953003 has 12 divisors (see below), whose sum is σ = 868810680. Its totient is φ = 424205056.

The previous prime is 643952999. The next prime is 643953017. The reversal of 643953003 is 300359346.

It is not a de Polignac number, because 643953003 - 2² = 643952999 is a prime.

It is not an unprimeable number, because it can be changed into a prime (643953043) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 413875 + ... + 415427.

It is an arithmetic number, because the mean of its divisors is an integer number (72400890).

Almost surely, 2^643953003 is an apocalyptic number.

643953003 is a deficient number, since it is larger than the sum of its proper divisors (224857677).

643953003 is an frugal number, since it uses more digits than its factorization.

643953003 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3198 (or 1645 counting only the distinct ones).

The product of its (nonzero) digits is 29160, while the sum is 33.

The square root of 643953003 is about 25376.2290933858. The cubic root of 643953003 is about 863.5445036161.

The spelling of 643953003 in words is "six hundred forty-three million, nine hundred fifty-three thousand, three".