205778649481 has 4 divisors (see below), whose sum is σ = 212416670464. Its totient is φ = 199140628500.

The previous prime is 205778649451. The next prime is 205778649487. The reversal of 205778649481 is 184946877502.

205778649481 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 205778649481 - 2¹¹ = 205778647433 is a prime.

It is a super-2 number, since 2×205778649481² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (205778649487) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3319010445 + ... + 3319010506.

It is an arithmetic number, because the mean of its divisors is an integer number (53104167616).

Almost surely, 2^205778649481 is an apocalyptic number.

It is an amenable number.

205778649481 is a deficient number, since it is larger than the sum of its proper divisors (6638020983).

205778649481 is an equidigital number, since it uses as much as digits as its factorization.

205778649481 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6638020982.

The product of its (nonzero) digits is 27095040, while the sum is 61.

The spelling of 205778649481 in words is "two hundred five billion, seven hundred seventy-eight million, six hundred forty-nine thousand, four hundred eighty-one".