643472671 has 4 divisors (see below), whose sum is σ = 649376200. Its totient is φ = 637569144.

The previous prime is 643472663. The next prime is 643472681. The reversal of 643472671 is 176274346.

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 643472671 - 2³ = 643472663 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643472681) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2951601 + ... + 2951818.

It is an arithmetic number, because the mean of its divisors is an integer number (162344050).

Almost surely, 2^643472671 is an apocalyptic number.

643472671 is a deficient number, since it is larger than the sum of its proper divisors (5903529).

643472671 is a wasteful number, since it uses less digits than its factorization.

643472671 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5903528.

The product of its digits is 169344, while the sum is 40.

The square root of 643472671 is about 25366.7631163300. The cubic root of 643472671 is about 863.3297409284.

The spelling of 643472671 in words is "six hundred forty-three million, four hundred seventy-two thousand, six hundred seventy-one".