3968218561 has 2 divisors, whose sum is σ = 3968218562. Its totient is φ = 3968218560.

The previous prime is 3968218531. The next prime is 3968218621. The reversal of 3968218561 is 1658128693.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 3520642225 + 447576336 = 59335^2 + 21156^2 .

It is a cyclic number.

It is not a de Polignac number, because 3968218561 - 2⁷ = 3968218433 is a prime.

It is not a weakly prime, because it can be changed into another prime (3968218531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1984109280 + 1984109281.

It is an arithmetic number, because the mean of its divisors is an integer number (1984109281).

Almost surely, 2^3968218561 is an apocalyptic number.

It is an amenable number.

3968218561 is a deficient number, since it is larger than the sum of its proper divisors (1).

3968218561 is an equidigital number, since it uses as much as digits as its factorization.

3968218561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 622080, while the sum is 49.

The square root of 3968218561 is about 62993.7977978785. The cubic root of 3968218561 is about 1583.1857105679.

The spelling of 3968218561 in words is "three billion, nine hundred sixty-eight million, two hundred eighteen thousand, five hundred sixty-one".