1643443439 has 4 divisors (see below), whose sum is σ = 1792847400. Its totient is φ = 1494039480.

The previous prime is 1643443433. The next prime is 1643443481. The reversal of 1643443439 is 9343443461.

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 1643443439 - 2⁸ = 1643443183 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1643443396 and 1643443405.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1643443433) 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, 74701964 + ... + 74701985.

It is an arithmetic number, because the mean of its divisors is an integer number (448211850).

Almost surely, 2^1643443439 is an apocalyptic number.

1643443439 is a deficient number, since it is larger than the sum of its proper divisors (149403961).

1643443439 is a wasteful number, since it uses less digits than its factorization.

1643443439 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 149403960.

The product of its digits is 373248, while the sum is 41.

The square root of 1643443439 is about 40539.4060020617. The cubic root of 1643443439 is about 1180.0984881407.

The spelling of 1643443439 in words is "one billion, six hundred forty-three million, four hundred forty-three thousand, four hundred thirty-nine".