644180241 has 4 divisors (see below), whose sum is σ = 858906992. Its totient is φ = 429453492.

The previous prime is 644180239. The next prime is 644180281. The reversal of 644180241 is 142081446.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 644180241 - 2¹ = 644180239 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 644180199 and 644180208.

It is not an unprimeable number, because it can be changed into a prime (644180221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 107363371 + ... + 107363376.

It is an arithmetic number, because the mean of its divisors is an integer number (214726748).

Almost surely, 2^644180241 is an apocalyptic number.

It is an amenable number.

644180241 is a deficient number, since it is larger than the sum of its proper divisors (214726751).

644180241 is a wasteful number, since it uses less digits than its factorization.

644180241 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 214726750.

The product of its (nonzero) digits is 6144, while the sum is 30.

The square root of 644180241 is about 25380.7060776488. The cubic root of 644180241 is about 863.6460674713.

The spelling of 644180241 in words is "six hundred forty-four million, one hundred eighty thousand, two hundred forty-one".