664425 has 18 divisors (see below), whose sum is σ = 1190462. Its totient is φ = 354240.

The previous prime is 664421. The next prime is 664427. The reversal of 664425 is 524466.

It is a happy number.

It can be written as a sum of positive squares in 3 ways, for example, as 110889 + 553536 = 333^2 + 744^2 .

It is not a de Polignac number, because 664425 - 2² = 664421 is a prime.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664421) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 1252 + ... + 1701.

2⁶⁶⁴⁴²⁵ is an apocalyptic number.

It is an amenable number.

664425 is a deficient number, since it is larger than the sum of its proper divisors (526037).

664425 is a wasteful number, since it uses less digits than its factorization.

664425 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2969 (or 2961 counting only the distinct ones).

The product of its digits is 5760, while the sum is 27.

The square root of 664425 is about 815.1226901516. The cubic root of 664425 is about 87.2600227127.

It can be divided in two parts, 664 and 425, that added together give a square (1089 = 33²).

The spelling of 664425 in words is "six hundred sixty-four thousand, four hundred twenty-five".