643396841 has 8 divisors (see below), whose sum is σ = 681657120. Its totient is φ = 605182528.

The previous prime is 643396837. The next prime is 643396849. The reversal of 643396841 is 148693346.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 643396841 - 2² = 643396837 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 643396792 and 643396801.

It is not an unprimeable number, because it can be changed into a prime (643396849) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19790 + ... + 40968.

It is an arithmetic number, because the mean of its divisors is an integer number (85207140).

Almost surely, 2^643396841 is an apocalyptic number.

It is an amenable number.

643396841 is a deficient number, since it is larger than the sum of its proper divisors (38260279).

643396841 is a wasteful number, since it uses less digits than its factorization.

643396841 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22983.

The product of its digits is 373248, while the sum is 44.

The square root of 643396841 is about 25365.2683999204. The cubic root of 643396841 is about 863.2958265816.

The spelling of 643396841 in words is "six hundred forty-three million, three hundred ninety-six thousand, eight hundred forty-one".