648661679 has 4 divisors (see below), whose sum is σ = 648726576. Its totient is φ = 648596784.

The previous prime is 648661661. The next prime is 648661681. The reversal of 648661679 is 976166846.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 976166846 = 2 ⋅488083423.

It is a cyclic number.

It is not a de Polignac number, because 648661679 - 2⁸ = 648661423 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 648661679.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (648631679) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13934 + ... + 38619.

It is an arithmetic number, because the mean of its divisors is an integer number (162181644).

Almost surely, 2^648661679 is an apocalyptic number.

648661679 is a deficient number, since it is larger than the sum of its proper divisors (64897).

648661679 is a wasteful number, since it uses less digits than its factorization.

648661679 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64896.

The product of its digits is 2612736, while the sum is 53.

The square root of 648661679 is about 25468.8374096660. The cubic root of 648661679 is about 865.6441809562.

The spelling of 648661679 in words is "six hundred forty-eight million, six hundred sixty-one thousand, six hundred seventy-nine".