664387 has 4 divisors (see below), whose sum is σ = 666520. Its totient is φ = 662256.

The previous prime is 664381. The next prime is 664403. The reversal of 664387 is 783466.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 783466 = 2 ⋅391733.

It is a cyclic number.

It is not a de Polignac number, because 664387 - 2³ = 664379 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (664381) 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, 498 + ... + 1255.

It is an arithmetic number, because the mean of its divisors is an integer number (166630).

2⁶⁶⁴³⁸⁷ is an apocalyptic number.

664387 is a deficient number, since it is larger than the sum of its proper divisors (2133).

664387 is a wasteful number, since it uses less digits than its factorization.

664387 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2132.

The product of its digits is 24192, while the sum is 34.

The square root of 664387 is about 815.0993804439. The cubic root of 664387 is about 87.2583591469.

The spelling of 664387 in words is "six hundred sixty-four thousand, three hundred eighty-seven".