664556841 has 27 divisors (see below), whose sum is σ = 1041009957. Its totient is φ = 408339360.

The previous prime is 664556839. The next prime is 664556897. The reversal of 664556841 is 148655466.

The square root of 664556841 is 25779.

It is a perfect power (a square), and thus also a powerful number.

664556841 is a `hidden beast` number, since 6 + 6 + 45 + 568 + 41 = 666.

664556841 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 3861225 + 660695616 = 1965^2 + 25704^2 .

It is not a de Polignac number, because 664556841 - 2¹ = 664556839 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (664556821) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 1005051 + ... + 1005711.

Almost surely, 2^664556841 is an apocalyptic number.

664556841 is the 25779-th square number.

664556841 is the 12890-th centered octagonal number.

It is an amenable number.

664556841 is a deficient number, since it is larger than the sum of its proper divisors (376453116).

664556841 is an equidigital number, since it uses as much as digits as its factorization.

664556841 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1354 (or 677 counting only the distinct ones).

The product of its digits is 691200, while the sum is 45.

The cubic root of 664556841 is about 872.6579396240.

The spelling of 664556841 in words is "six hundred sixty-four million, five hundred fifty-six thousand, eight hundred forty-one".