648213561 has 12 divisors (see below), whose sum is σ = 936718692. Its totient is φ = 431953056.

The previous prime is 648213551. The next prime is 648213571. The reversal of 648213561 is 165312846.

It is a happy number.

648213561 is a `hidden beast` number, since 6 + 4 + 82 + 13 + 561 = 666.

648213561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (648213551) and next prime (648213571).

It can be written as a sum of positive squares in 2 ways, for example, as 427869225 + 220344336 = 20685^2 + 14844^2 .

It is not a de Polignac number, because 648213561 - 2⁵ = 648213529 is a prime.

It is not an unprimeable number, because it can be changed into a prime (648213521) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7755 + ... + 36831.

It is an arithmetic number, because the mean of its divisors is an integer number (78059891).

Almost surely, 2^648213561 is an apocalyptic number.

It is an amenable number.

648213561 is a deficient number, since it is larger than the sum of its proper divisors (288505131).

648213561 is a wasteful number, since it uses less digits than its factorization.

648213561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31560 (or 31557 counting only the distinct ones).

The product of its digits is 34560, while the sum is 36.

The square root of 648213561 is about 25460.0385113613. The cubic root of 648213561 is about 865.4447960209. Note that the first 3 decimals are identical.

The spelling of 648213561 in words is "six hundred forty-eight million, two hundred thirteen thousand, five hundred sixty-one".