644130641 has 8 divisors (see below), whose sum is σ = 803072064. Its totient is φ = 501919920.

The previous prime is 644130601. The next prime is 644130661. The reversal of 644130641 is 146031446.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 644130641 - 2⁶ = 644130577 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (644130601) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4182590 + ... + 4182743.

It is an arithmetic number, because the mean of its divisors is an integer number (100384008).

Almost surely, 2^644130641 is an apocalyptic number.

It is an amenable number.

644130641 is a deficient number, since it is larger than the sum of its proper divisors (158941423).

644130641 is a wasteful number, since it uses less digits than its factorization.

644130641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8365351.

The product of its (nonzero) digits is 6912, while the sum is 29.

The square root of 644130641 is about 25379.7289386628. The cubic root of 644130641 is about 863.6239008261.

The spelling of 644130641 in words is "six hundred forty-four million, one hundred thirty thousand, six hundred forty-one".