2543684639 has 4 divisors (see below), whose sum is σ = 2543825256. Its totient is φ = 2543544024.

The previous prime is 2543684599. The next prime is 2543684659. The reversal of 2543684639 is 9364863452.

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 2543684639 - 2²⁴ = 2526907423 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 (2543684659) 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, 38324 + ... + 80969.

It is an arithmetic number, because the mean of its divisors is an integer number (635956314).

Almost surely, 2^2543684639 is an apocalyptic number.

2543684639 is a deficient number, since it is larger than the sum of its proper divisors (140617).

2543684639 is a wasteful number, since it uses less digits than its factorization.

2543684639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 140616.

The product of its digits is 3732480, while the sum is 50.

The square root of 2543684639 is about 50434.9545355203. The cubic root of 2543684639 is about 1365.0684288129.

The spelling of 2543684639 in words is "two billion, five hundred forty-three million, six hundred eighty-four thousand, six hundred thirty-nine".