640441468081 has 2 divisors, whose sum is σ = 640441468082. Its totient is φ = 640441468080.

The previous prime is 640441467997. The next prime is 640441468111. The reversal of 640441468081 is 180864144046.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 451550400625 + 188891067456 = 671975^2 + 434616^2 .

It is a cyclic number.

It is not a de Polignac number, because 640441468081 - 2¹⁵ = 640441435313 is a prime.

It is a super-2 number, since 2×640441468081² (a number of 24 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (640441468781) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320220734040 + 320220734041.

It is an arithmetic number, because the mean of its divisors is an integer number (320220734041).

Almost surely, 2^640441468081 is an apocalyptic number.

It is an amenable number.

640441468081 is a deficient number, since it is larger than the sum of its proper divisors (1).

640441468081 is an equidigital number, since it uses as much as digits as its factorization.

640441468081 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 589824, while the sum is 46.

It can be divided in two parts, 64044 and 1468081, that added together give a triangular number (1532125 = T₁₇₅₀).

The spelling of 640441468081 in words is "six hundred forty billion, four hundred forty-one million, four hundred sixty-eight thousand, eighty-one".