664705 has 8 divisors (see below), whose sum is σ = 819432. Its totient is φ = 517248.

The previous prime is 664693. The next prime is 664711. The reversal of 664705 is 507466.

664705 = 576² + 577².

It can be written as a sum of positive squares in 4 ways, for example, as 128881 + 535824 = 359^2 + 732^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 664705 - 2⁹ = 664193 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1612 + ... + 1981.

It is an arithmetic number, because the mean of its divisors is an integer number (102429).

2⁶⁶⁴⁷⁰⁵ is an apocalyptic number.

664705 is the 577-th centered square number.

It is an amenable number.

664705 is a deficient number, since it is larger than the sum of its proper divisors (154727).

664705 is a wasteful number, since it uses less digits than its factorization.

664705 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3635.

The product of its (nonzero) digits is 5040, while the sum is 28.

The square root of 664705 is about 815.2944253458. The cubic root of 664705 is about 87.2722786106.

It can be divided in two parts, 664 and 705, that added together give a square (1369 = 37²).

The spelling of 664705 in words is "six hundred sixty-four thousand, seven hundred five".