640321421321429 has 2 divisors, whose sum is σ = 640321421321430. Its totient is φ = 640321421321428.

The previous prime is 640321421321401. The next prime is 640321421321473. The reversal of 640321421321429 is 924123124123046.

640321421321429 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an a-pointer prime, because the next prime (640321421321473) can be obtained adding 640321421321429 to its sum of digits (44).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 513352019796529 + 126969401524900 = 22657273^2 + 11268070^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-640321421321429 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 640321421321429.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (640321421321629) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320160710660714 + 320160710660715.

It is an arithmetic number, because the mean of its divisors is an integer number (320160710660715).

Almost surely, 2^{640321421321429} is an apocalyptic number.

It is an amenable number.

640321421321429 is a deficient number, since it is larger than the sum of its proper divisors (1).

640321421321429 is an equidigital number, since it uses as much as digits as its factorization.

640321421321429 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 497664, while the sum is 44.

The spelling of 640321421321429 in words is "six hundred forty trillion, three hundred twenty-one billion, four hundred twenty-one million, three hundred twenty-one thousand, four hundred twenty-nine".