643857403 has 6 divisors (see below), whose sum is σ = 748977036. Its totient is φ = 551877732.

The previous prime is 643857373. The next prime is 643857421. The reversal of 643857403 is 304758346.

It is not a de Polignac number, because 643857403 - 2¹⁷ = 643726331 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (643857433) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 6569925 + ... + 6570022.

It is an arithmetic number, because the mean of its divisors is an integer number (124829506).

Almost surely, 2^643857403 is an apocalyptic number.

643857403 is a deficient number, since it is larger than the sum of its proper divisors (105119633).

643857403 is a wasteful number, since it uses less digits than its factorization.

643857403 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13139961 (or 13139954 counting only the distinct ones).

The product of its (nonzero) digits is 241920, while the sum is 40.

The square root of 643857403 is about 25374.3453708662. The cubic root of 643857403 is about 863.5017681267.

The spelling of 643857403 in words is "six hundred forty-three million, eight hundred fifty-seven thousand, four hundred three".