640815319873 has 4 divisors (see below), whose sum is σ = 640827632560. Its totient is φ = 640803007188.

The previous prime is 640815319847. The next prime is 640815319901. The reversal of 640815319873 is 378913518046.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 640815319873 - 2³⁷ = 503376366401 is a prime.

It is a super-2 number, since 2×640815319873² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (640815389873) 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, 6077943 + ... + 6182476.

It is an arithmetic number, because the mean of its divisors is an integer number (160206908140).

Almost surely, 2^640815319873 is an apocalyptic number.

It is an amenable number.

640815319873 is a deficient number, since it is larger than the sum of its proper divisors (12312687).

640815319873 is a wasteful number, since it uses less digits than its factorization.

640815319873 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12312686.

The product of its (nonzero) digits is 4354560, while the sum is 55.

The spelling of 640815319873 in words is "six hundred forty billion, eight hundred fifteen million, three hundred nineteen thousand, eight hundred seventy-three".