664679391 has 8 divisors (see below), whose sum is σ = 916799280. Its totient is φ = 427839552.

The previous prime is 664679387. The next prime is 664679417. The reversal of 664679391 is 193976466.

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

It is not a de Polignac number, because 664679391 - 2² = 664679387 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664672391) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3819910 + ... + 3820083.

It is an arithmetic number, because the mean of its divisors is an integer number (114599910).

Almost surely, 2^664679391 is an apocalyptic number.

664679391 is a deficient number, since it is larger than the sum of its proper divisors (252119889).

664679391 is a wasteful number, since it uses less digits than its factorization.

664679391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7640025.

The product of its digits is 1469664, while the sum is 51.

The square root of 664679391 is about 25781.3768251426. The cubic root of 664679391 is about 872.7115782048.

The spelling of 664679391 in words is "six hundred sixty-four million, six hundred seventy-nine thousand, three hundred ninety-one".