205778649451 has 2 divisors, whose sum is σ = 205778649452. Its totient is φ = 205778649450.

The previous prime is 205778649407. The next prime is 205778649487. The reversal of 205778649451 is 154946877502.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 205778649451 - 2²⁷ = 205644431723 is a prime.

It is not a weakly prime, because it can be changed into another prime (205778649151) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102889324725 + 102889324726.

It is an arithmetic number, because the mean of its divisors is an integer number (102889324726).

Almost surely, 2^205778649451 is an apocalyptic number.

205778649451 is a deficient number, since it is larger than the sum of its proper divisors (1).

205778649451 is an equidigital number, since it uses as much as digits as its factorization.

205778649451 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 16934400, while the sum is 58.

The spelling of 205778649451 in words is "two hundred five billion, seven hundred seventy-eight million, six hundred forty-nine thousand, four hundred fifty-one".