643698243 has 12 divisors (see below), whose sum is σ = 930018960. Its totient is φ = 429024816.

The previous prime is 643698203. The next prime is 643698257. The reversal of 643698243 is 342896346.

It is not a de Polignac number, because 643698243 - 2¹² = 643694147 is a prime.

It is not an unprimeable number, because it can be changed into a prime (643698203) 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, 48330 + ... + 60192.

It is an arithmetic number, because the mean of its divisors is an integer number (77501580).

Almost surely, 2^643698243 is an apocalyptic number.

643698243 is a deficient number, since it is larger than the sum of its proper divisors (286320717).

643698243 is a wasteful number, since it uses less digits than its factorization.

643698243 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17898 (or 17895 counting only the distinct ones).

The product of its digits is 746496, while the sum is 45.

The square root of 643698243 is about 25371.2089384799. The cubic root of 643698243 is about 863.4306104103.

The spelling of 643698243 in words is "six hundred forty-three million, six hundred ninety-eight thousand, two hundred forty-three".