1643365673 has 16 divisors (see below), whose sum is σ = 1752814080. Its totient is φ = 1535385600.

The previous prime is 1643365657. The next prime is 1643365679. The reversal of 1643365673 is 3765633461.

It is a happy number.

It is not a de Polignac number, because 1643365673 - 2⁴ = 1643365657 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1643365679) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2563433 + ... + 2564073.

It is an arithmetic number, because the mean of its divisors is an integer number (109550880).

Almost surely, 2^1643365673 is an apocalyptic number.

It is an amenable number.

1643365673 is a deficient number, since it is larger than the sum of its proper divisors (109448407).

1643365673 is a wasteful number, since it uses less digits than its factorization.

1643365673 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1528.

The product of its digits is 816480, while the sum is 44.

The square root of 1643365673 is about 40538.4468498733. The cubic root of 1643365673 is about 1180.0798741776.

The spelling of 1643365673 in words is "one billion, six hundred forty-three million, three hundred sixty-five thousand, six hundred seventy-three".