664393 has 4 divisors (see below), whose sum is σ = 679888. Its totient is φ = 648900.

The previous prime is 664381. The next prime is 664403. The reversal of 664393 is 393466.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 664393 - 2⁹ = 663881 is a prime.

It is a Duffinian number.

It is a plaindrome in base 9.

It is not an unprimeable number, because it can be changed into a prime (664193) 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, 7683 + ... + 7768.

It is an arithmetic number, because the mean of its divisors is an integer number (169972).

2⁶⁶⁴³⁹³ is an apocalyptic number.

It is an amenable number.

664393 is a deficient number, since it is larger than the sum of its proper divisors (15495).

664393 is a wasteful number, since it uses less digits than its factorization.

664393 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15494.

The product of its digits is 11664, while the sum is 31.

The square root of 664393 is about 815.1030609684. The cubic root of 664393 is about 87.2586218194.

The spelling of 664393 in words is "six hundred sixty-four thousand, three hundred ninety-three".