664465 has 4 divisors (see below), whose sum is σ = 797364. Its totient is φ = 531568.

The previous prime is 664459. The next prime is 664471. The reversal of 664465 is 564466.

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 (664459) and next prime (664471).

It can be written as a sum of positive squares in 2 ways, for example, as 463761 + 200704 = 681^2 + 448^2 .

It is a cyclic number.

It is not a de Polignac number, because 664465 - 2¹³ = 656273 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66442 + ... + 66451.

It is an arithmetic number, because the mean of its divisors is an integer number (199341).

2⁶⁶⁴⁴⁶⁵ is an apocalyptic number.

It is an amenable number.

664465 is a deficient number, since it is larger than the sum of its proper divisors (132899).

664465 is a wasteful number, since it uses less digits than its factorization.

664465 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 132898.

The product of its digits is 17280, while the sum is 31.

The square root of 664465 is about 815.1472259660. The cubic root of 664465 is about 87.2617737660.

Subtracting from 664465 its reverse (564466), we obtain a palindrome (99999).

The spelling of 664465 in words is "six hundred sixty-four thousand, four hundred sixty-five".