644000424541 has 4 divisors (see below), whose sum is σ = 644851152412. Its totient is φ = 643149696672.

The previous prime is 644000424467. The next prime is 644000424559. The reversal of 644000424541 is 145424000446.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 145424000446 = 2 ⋅72712000223.

It can be written as a sum of positive squares in 2 ways, for example, as 205684925625 + 438315498916 = 453525^2 + 662054^2 .

It is a cyclic number.

It is not a de Polignac number, because 644000424541 - 2⁷ = 644000424413 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 644000424497 and 644000424506.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644000424941) 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, 425362800 + ... + 425364313.

It is an arithmetic number, because the mean of its divisors is an integer number (161212788103).

Almost surely, 2^644000424541 is an apocalyptic number.

It is an amenable number.

644000424541 is a deficient number, since it is larger than the sum of its proper divisors (850727871).

644000424541 is an equidigital number, since it uses as much as digits as its factorization.

644000424541 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 850727870.

The product of its (nonzero) digits is 61440, while the sum is 34.

Adding to 644000424541 its reverse (145424000446), we get a palindrome (789424424987).

The spelling of 644000424541 in words is "six hundred forty-four billion, four hundred twenty-four thousand, five hundred forty-one".