664555 has 4 divisors (see below), whose sum is σ = 797472. Its totient is φ = 531640.

The previous prime is 664549. The next prime is 664561. The reversal of 664555 is 555466.

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

It is an interprime number because it is at equal distance from previous prime (664549) and next prime (664561).

It is not a de Polignac number, because 664555 - 2⁷ = 664427 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66451 + ... + 66460.

It is an arithmetic number, because the mean of its divisors is an integer number (199368).

2⁶⁶⁴⁵⁵⁵ is an apocalyptic number.

664555 is a deficient number, since it is larger than the sum of its proper divisors (132917).

664555 is a wasteful number, since it uses less digits than its factorization.

664555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 132916.

The product of its digits is 18000, while the sum is 31.

The square root of 664555 is about 815.2024288482. The cubic root of 664555 is about 87.2657133791.

The spelling of 664555 in words is "six hundred sixty-four thousand, five hundred fifty-five".