648393393845 has 4 divisors (see below), whose sum is σ = 778072072620. Its totient is φ = 518714715072.

The previous prime is 648393393827. The next prime is 648393393911. The reversal of 648393393845 is 548393393846.

648393393845 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 548393393846 = 2 ⋅274196696923.

It can be written as a sum of positive squares in 2 ways, for example, as 312465348196 + 335928045649 = 558986^2 + 579593^2 .

It is a cyclic number.

It is not a de Polignac number, because 648393393845 - 2⁸ = 648393393589 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 64839339380 + ... + 64839339389.

It is an arithmetic number, because the mean of its divisors is an integer number (194518018155).

Almost surely, 2^648393393845 is an apocalyptic number.

It is an amenable number.

648393393845 is a deficient number, since it is larger than the sum of its proper divisors (129678678775).

648393393845 is a wasteful number, since it uses less digits than its factorization.

648393393845 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 129678678774.

The product of its digits is 201553920, while the sum is 65.

Subtracting from 648393393845 its reverse (548393393846), we obtain a palindrome (99999999999).

The spelling of 648393393845 in words is "six hundred forty-eight billion, three hundred ninety-three million, three hundred ninety-three thousand, eight hundred forty-five".