664417 has 4 divisors (see below), whose sum is σ = 715540. Its totient is φ = 613296.

The previous prime is 664403. The next prime is 664421. The reversal of 664417 is 714466.

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

It can be written as a sum of positive squares in 2 ways, for example, as 398161 + 266256 = 631^2 + 516^2 .

It is a cyclic number.

It is not a de Polignac number, because 664417 - 2⁷ = 664289 is a prime.

It is a super-4 number, since 4×664417⁴ (a number of 24 digits) contains 4444 as substring.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664427) 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, 25542 + ... + 25567.

It is an arithmetic number, because the mean of its divisors is an integer number (178885).

2⁶⁶⁴⁴¹⁷ is an apocalyptic number.

It is an amenable number.

664417 is a deficient number, since it is larger than the sum of its proper divisors (51123).

664417 is a wasteful number, since it uses less digits than its factorization.

664417 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51122.

The product of its digits is 4032, while the sum is 28.

The square root of 664417 is about 815.1177829001. The cubic root of 664417 is about 87.2596724936.

It can be divided in two parts, 664 and 417, that added together give a triangular number (1081 = T₄₆).

The spelling of 664417 in words is "six hundred sixty-four thousand, four hundred seventeen".