644000424497 has 4 divisors (see below), whose sum is σ = 651759465840. Its totient is φ = 636241383156.

The previous prime is 644000424467. The next prime is 644000424559. The reversal of 644000424497 is 794424000446.

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, and also an emirpimes, since its reverse is a distinct semiprime: 794424000446 = 2 ⋅397212000223.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-644000424497 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (644000424467) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3879520547 + ... + 3879520712.

It is an arithmetic number, because the mean of its divisors is an integer number (162939866460).

Almost surely, 2^644000424497 is an apocalyptic number.

It is an amenable number.

644000424497 is a deficient number, since it is larger than the sum of its proper divisors (7759041343).

644000424497 is an equidigital number, since it uses as much as digits as its factorization.

644000424497 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7759041342.

The product of its (nonzero) digits is 774144, while the sum is 44.

The spelling of 644000424497 in words is "six hundred forty-four billion, four hundred twenty-four thousand, four hundred ninety-seven".