664381905443 has 4 divisors (see below), whose sum is σ = 664781415168. Its totient is φ = 663982395720.

The previous prime is 664381905391. The next prime is 664381905497. The reversal of 664381905443 is 344509183466.

664381905443 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 664381905443 - 2⁶ = 664381905379 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (664381905043) 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, 199752368 + ... + 199755693.

It is an arithmetic number, because the mean of its divisors is an integer number (166195353792).

Almost surely, 2^664381905443 is an apocalyptic number.

664381905443 is a deficient number, since it is larger than the sum of its proper divisors (399509725).

664381905443 is a wasteful number, since it uses less digits than its factorization.

664381905443 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 399509724.

The product of its (nonzero) digits is 7464960, while the sum is 53.

The spelling of 664381905443 in words is "six hundred sixty-four billion, three hundred eighty-one million, nine hundred five thousand, four hundred forty-three".