640323355361 has 4 divisors (see below), whose sum is σ = 640332720324. Its totient is φ = 640313990400.

The previous prime is 640323355307. The next prime is 640323355381. The reversal of 640323355361 is 163553323046.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 292930995361 + 347392360000 = 541231^2 + 589400^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-640323355361 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (640323355381) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4579160 + ... + 4716921.

It is an arithmetic number, because the mean of its divisors is an integer number (160083180081).

Almost surely, 2^640323355361 is an apocalyptic number.

It is an amenable number.

640323355361 is a deficient number, since it is larger than the sum of its proper divisors (9364963).

640323355361 is an equidigital number, since it uses as much as digits as its factorization.

640323355361 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9364962.

The product of its (nonzero) digits is 583200, while the sum is 41.

The spelling of 640323355361 in words is "six hundred forty billion, three hundred twenty-three million, three hundred fifty-five thousand, three hundred sixty-one".