664513 has 4 divisors (see below), whose sum is σ = 703620. Its totient is φ = 625408.

The previous prime is 664511. The next prime is 664529. The reversal of 664513 is 315466.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 315466 = 2 ⋅157733.

It can be written as a sum of positive squares in 2 ways, for example, as 369664 + 294849 = 608^2 + 543^2 .

It is a cyclic number.

It is not a de Polignac number, because 664513 - 2¹ = 664511 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 (664511) 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, 19528 + ... + 19561.

It is an arithmetic number, because the mean of its divisors is an integer number (175905).

2⁶⁶⁴⁵¹³ is an apocalyptic number.

It is an amenable number.

664513 is a deficient number, since it is larger than the sum of its proper divisors (39107).

664513 is a wasteful number, since it uses less digits than its factorization.

664513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39106.

The product of its digits is 2160, while the sum is 25.

The square root of 664513 is about 815.1766679684. The cubic root of 664513 is about 87.2638749373.

Adding to 664513 its reverse (315466), we get a palindrome (979979).

The spelling of 664513 in words is "six hundred sixty-four thousand, five hundred thirteen".