664716943 has 4 divisors (see below), whose sum is σ = 725145768. Its totient is φ = 604288120.

The previous prime is 664716931. The next prime is 664716953. The reversal of 664716943 is 349617466.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-664716943 is a prime.

It is a super-2 number, since 2×664716943² = 883697228622530498, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 664716893 and 664716902.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664716953) 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, 30214396 + ... + 30214417.

It is an arithmetic number, because the mean of its divisors is an integer number (181286442).

Almost surely, 2^664716943 is an apocalyptic number.

664716943 is a deficient number, since it is larger than the sum of its proper divisors (60428825).

664716943 is a wasteful number, since it uses less digits than its factorization.

664716943 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60428824.

The product of its digits is 653184, while the sum is 46.

The square root of 664716943 is about 25782.1050924861. The cubic root of 664716943 is about 872.7280129193.

The spelling of 664716943 in words is "six hundred sixty-four million, seven hundred sixteen thousand, nine hundred forty-three".