664719817 has 8 divisors (see below), whose sum is σ = 688501440. Its totient is φ = 640995600.

The previous prime is 664719791. The next prime is 664719829. The reversal of 664719817 is 718917466.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-664719817 is a prime.

It is a super-2 number, since 2×664719817² = 883704870225026978, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (664719857) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9942 + ... + 37792.

It is an arithmetic number, because the mean of its divisors is an integer number (86062680).

Almost surely, 2^664719817 is an apocalyptic number.

It is an amenable number.

664719817 is a deficient number, since it is larger than the sum of its proper divisors (23781623).

664719817 is a wasteful number, since it uses less digits than its factorization.

664719817 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28703.

The product of its digits is 508032, while the sum is 49.

The square root of 664719817 is about 25782.1608287591. The cubic root of 664719817 is about 872.7292707061.

The spelling of 664719817 in words is "six hundred sixty-four million, seven hundred nineteen thousand, eight hundred seventeen".