648778987 has 2 divisors, whose sum is σ = 648778988. Its totient is φ = 648778986.

The previous prime is 648778967. The next prime is 648778993. The reversal of 648778987 is 789877846.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 648778987 - 2¹⁹ = 648254699 is a prime.

It is not a weakly prime, because it can be changed into another prime (648778967) 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 as a sum of consecutive naturals, namely, 324389493 + 324389494.

It is an arithmetic number, because the mean of its divisors is an integer number (324389494).

Almost surely, 2^648778987 is an apocalyptic number.

648778987 is a deficient number, since it is larger than the sum of its proper divisors (1).

648778987 is an equidigital number, since it uses as much as digits as its factorization.

648778987 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 37933056, while the sum is 64.

The square root of 648778987 is about 25471.1402767917. The cubic root of 648778987 is about 865.6963606312.

The spelling of 648778987 in words is "six hundred forty-eight million, seven hundred seventy-eight thousand, nine hundred eighty-seven".