640051716365 has 4 divisors (see below), whose sum is σ = 768062059644. Its totient is φ = 512041373088.

The previous prime is 640051716361. The next prime is 640051716383. The reversal of 640051716365 is 563617150046.

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 159285599236 + 480766117129 = 399106^2 + 693373^2 .

It is a cyclic number.

It is not a de Polignac number, because 640051716365 - 2² = 640051716361 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640051716361) 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, 64005171632 + ... + 64005171641.

It is an arithmetic number, because the mean of its divisors is an integer number (192015514911).

Almost surely, 2^640051716365 is an apocalyptic number.

It is an amenable number.

640051716365 is a deficient number, since it is larger than the sum of its proper divisors (128010343279).

640051716365 is a wasteful number, since it uses less digits than its factorization.

640051716365 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 128010343278.

The product of its (nonzero) digits is 453600, while the sum is 44.

The spelling of 640051716365 in words is "six hundred forty billion, fifty-one million, seven hundred sixteen thousand, three hundred sixty-five".