664001641 has 4 divisors (see below), whose sum is σ = 664061652. Its totient is φ = 663941632.

The previous prime is 664001633. The next prime is 664001647. The reversal of 664001641 is 146100466.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 125529616 + 538472025 = 11204^2 + 23205^2 .

It is a cyclic number.

It is not a de Polignac number, because 664001641 - 2³ = 664001633 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (664001647) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 8056 + ... + 37321.

It is an arithmetic number, because the mean of its divisors is an integer number (166015413).

Almost surely, 2^664001641 is an apocalyptic number.

It is an amenable number.

664001641 is a deficient number, since it is larger than the sum of its proper divisors (60011).

664001641 is a wasteful number, since it uses less digits than its factorization.

664001641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60010.

The product of its (nonzero) digits is 3456, while the sum is 28.

The square root of 664001641 is about 25768.2292950059. The cubic root of 664001641 is about 872.4148529809.

The spelling of 664001641 in words is "six hundred sixty-four million, one thousand, six hundred forty-one".