640666203433 has 2 divisors, whose sum is σ = 640666203434. Its totient is φ = 640666203432.

The previous prime is 640666203427. The next prime is 640666203451. The reversal of 640666203433 is 334302666046.

640666203433 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 550865293209 + 89800910224 = 742203^2 + 299668^2 .

It is a cyclic number.

It is not a de Polignac number, because 640666203433 - 2²¹ = 640664106281 is a prime.

It is a super-4 number, since 4×640666203433⁴ (a number of 48 digits) contains 4444 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 640666203433.

It is not a weakly prime, because it can be changed into another prime (640666203533) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320333101716 + 320333101717.

It is an arithmetic number, because the mean of its divisors is an integer number (320333101717).

Almost surely, 2^640666203433 is an apocalyptic number.

It is an amenable number.

640666203433 is a deficient number, since it is larger than the sum of its proper divisors (1).

640666203433 is an equidigital number, since it uses as much as digits as its factorization.

640666203433 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1119744, while the sum is 43.

Adding to 640666203433 its reverse (334302666046), we get a palindrome (974968869479).

The spelling of 640666203433 in words is "six hundred forty billion, six hundred sixty-six million, two hundred three thousand, four hundred thirty-three".