648864557 has 18 divisors (see below), whose sum is σ = 722383914. Its totient is φ = 582387520.

The previous prime is 648864553. The next prime is 648864571. The reversal of 648864557 is 755468846.

It is a happy number.

It can be written as a sum of positive squares in 3 ways, for example, as 105555076 + 543309481 = 10274^2 + 23309^2 .

It is not a de Polignac number, because 648864557 - 2² = 648864553 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 648864499 and 648864508.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (648864553) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 958103 + ... + 958779.

Almost surely, 2^648864557 is an apocalyptic number.

It is an amenable number.

648864557 is a deficient number, since it is larger than the sum of its proper divisors (73519357).

648864557 is an equidigital number, since it uses as much as digits as its factorization.

648864557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 877 (or 777 counting only the distinct ones).

The product of its digits is 6451200, while the sum is 53.

The square root of 648864557 is about 25472.8199656026. The cubic root of 648864557 is about 865.7344189852.

The spelling of 648864557 in words is "six hundred forty-eight million, eight hundred sixty-four thousand, five hundred fifty-seven".