1643919543 has 48 divisors (see below), whose sum is σ = 2822916096. Its totient is φ = 936502560.

The previous prime is 1643919527. The next prime is 1643919547. The reversal of 1643919543 is 3459193461.

1643919543 is a `hidden beast` number, since 1 + 64 + 39 + 19 + 543 = 666.

It is not a de Polignac number, because 1643919543 - 2⁴ = 1643919527 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1643919547) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 633178 + ... + 635768.

It is an arithmetic number, because the mean of its divisors is an integer number (58810752).

Almost surely, 2^1643919543 is an apocalyptic number.

1643919543 is a deficient number, since it is larger than the sum of its proper divisors (1178996553).

1643919543 is an equidigital number, since it uses as much as digits as its factorization.

1643919543 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2986 (or 2974 counting only the distinct ones).

The product of its digits is 349920, while the sum is 45.

The square root of 1643919543 is about 40545.2776905030. The cubic root of 1643919543 is about 1180.2124349409.

The spelling of 1643919543 in words is "one billion, six hundred forty-three million, nine hundred nineteen thousand, five hundred forty-three".