644501141 has 4 divisors (see below), whose sum is σ = 644592672. Its totient is φ = 644409612.

The previous prime is 644501131. The next prime is 644501153. The reversal of 644501141 is 141105446.

644501141 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-644501141 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 644501141.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644501111) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 34235 + ... + 49608.

It is an arithmetic number, because the mean of its divisors is an integer number (161148168).

Almost surely, 2^644501141 is an apocalyptic number.

It is an amenable number.

644501141 is a deficient number, since it is larger than the sum of its proper divisors (91531).

644501141 is an equidigital number, since it uses as much as digits as its factorization.

644501141 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 91530.

The product of its (nonzero) digits is 1920, while the sum is 26.

The square root of 644501141 is about 25387.0270216896. The cubic root of 644501141 is about 863.7894528150.

Adding to 644501141 its reverse (141105446), we get a palindrome (785606587).

The spelling of 644501141 in words is "six hundred forty-four million, five hundred one thousand, one hundred forty-one".