640783383881 has 2 divisors, whose sum is σ = 640783383882. Its totient is φ = 640783383880.

The previous prime is 640783383841. The next prime is 640783383907. The reversal of 640783383881 is 188383387046.

640783383881 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 406221396025 + 234561987856 = 637355^2 + 484316^2 .

It is a cyclic number.

It is not a de Polignac number, because 640783383881 - 2⁶ = 640783383817 is a prime.

It is a super-2 number, since 2×640783383881² (a number of 24 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 640783383881.

It is not a weakly prime, because it can be changed into another prime (640783383841) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320391691940 + 320391691941.

It is an arithmetic number, because the mean of its divisors is an integer number (320391691941).

Almost surely, 2^640783383881 is an apocalyptic number.

It is an amenable number.

640783383881 is a deficient number, since it is larger than the sum of its proper divisors (1).

640783383881 is an equidigital number, since it uses as much as digits as its factorization.

640783383881 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 18579456, while the sum is 59.

The spelling of 640783383881 in words is "six hundred forty billion, seven hundred eighty-three million, three hundred eighty-three thousand, eight hundred eighty-one".