643517543 has 4 divisors (see below), whose sum is σ = 654424680. Its totient is φ = 632610408.

The previous prime is 643517531. The next prime is 643517551. The reversal of 643517543 is 345715346.

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 643517543 - 2⁴ = 643517527 is a prime.

It is a super-2 number, since 2×643517543² = 828229656297513698, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 643517497 and 643517506.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643517503) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5453480 + ... + 5453597.

It is an arithmetic number, because the mean of its divisors is an integer number (163606170).

Almost surely, 2^643517543 is an apocalyptic number.

643517543 is a deficient number, since it is larger than the sum of its proper divisors (10907137).

643517543 is a wasteful number, since it uses less digits than its factorization.

643517543 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10907136.

The product of its digits is 151200, while the sum is 38.

The square root of 643517543 is about 25367.6475653538. The cubic root of 643517543 is about 863.3498083083.

The spelling of 643517543 in words is "six hundred forty-three million, five hundred seventeen thousand, five hundred forty-three".