644510893841 has 2 divisors, whose sum is σ = 644510893842. Its totient is φ = 644510893840.

The previous prime is 644510893787. The next prime is 644510893931. The reversal of 644510893841 is 148398015446.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 603567394816 + 40943499025 = 776896^2 + 202345^2 .

It is a cyclic number.

It is not a de Polignac number, because 644510893841 - 2¹⁴ = 644510877457 is a prime.

It is not a weakly prime, because it can be changed into another prime (644510893141) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322255446920 + 322255446921.

It is an arithmetic number, because the mean of its divisors is an integer number (322255446921).

Almost surely, 2^644510893841 is an apocalyptic number.

It is an amenable number.

644510893841 is a deficient number, since it is larger than the sum of its proper divisors (1).

644510893841 is an equidigital number, since it uses as much as digits as its factorization.

644510893841 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3317760, while the sum is 53.

It can be divided in two parts, 644510 and 893841, that added together give a palindrome (1538351).

The spelling of 644510893841 in words is "six hundred forty-four billion, five hundred ten million, eight hundred ninety-three thousand, eight hundred forty-one".