219978557549 has 2 divisors, whose sum is σ = 219978557550. Its totient is φ = 219978557548.

The previous prime is 219978557543. The next prime is 219978557581. The reversal of 219978557549 is 945755879912.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 151977564649 + 68000992900 = 389843^2 + 260770^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-219978557549 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (219978557543) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 109989278774 + 109989278775.

It is an arithmetic number, because the mean of its divisors is an integer number (109989278775).

Almost surely, 2^219978557549 is an apocalyptic number.

It is an amenable number.

219978557549 is a deficient number, since it is larger than the sum of its proper divisors (1).

219978557549 is an equidigital number, since it uses as much as digits as its factorization.

219978557549 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 285768000, while the sum is 71.

The spelling of 219978557549 in words is "two hundred nineteen billion, nine hundred seventy-eight million, five hundred fifty-seven thousand, five hundred forty-nine".