664906725 has 90 divisors (see below), whose sum is σ = 1432934514. Its totient is φ = 303912000.

The previous prime is 664906673. The next prime is 664906757. The reversal of 664906725 is 527609466.

It can be written as a sum of positive squares in 3 ways, for example, as 26687556 + 638219169 = 5166^2 + 25263^2 .

It is not a de Polignac number, because 664906725 - 2¹⁷ = 664775653 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 89 ways as a sum of consecutive naturals, for example, 95875 + ... + 102575.

Almost surely, 2^664906725 is an apocalyptic number.

It is an amenable number.

664906725 is an abundant number, since it is smaller than the sum of its proper divisors (768027789).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

664906725 is a wasteful number, since it uses less digits than its factorization.

664906725 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6737 (or 6716 counting only the distinct ones).

The product of its (nonzero) digits is 544320, while the sum is 45.

The square root of 664906725 is about 25785.7853283548. The cubic root of 664906725 is about 872.8110619570.

The spelling of 664906725 in words is "six hundred sixty-four million, nine hundred six thousand, seven hundred twenty-five".