205120551 has 4 divisors (see below), whose sum is σ = 273494072. Its totient is φ = 136747032.

The previous prime is 205120541. The next prime is 205120571. The reversal of 205120551 is 155021502.

205120551 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.

It is not a de Polignac number, because 205120551 - 2⁵ = 205120519 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205120501) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 34186756 + ... + 34186761.

It is an arithmetic number, because the mean of its divisors is an integer number (68373518).

Almost surely, 2^205120551 is an apocalyptic number.

205120551 is a deficient number, since it is larger than the sum of its proper divisors (68373521).

205120551 is an equidigital number, since it uses as much as digits as its factorization.

205120551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68373520.

The product of its (nonzero) digits is 500, while the sum is 21.

The square root of 205120551 is about 14322.0302680870. The cubic root of 205120551 is about 589.7524107185.

The spelling of 205120551 in words is "two hundred five million, one hundred twenty thousand, five hundred fifty-one".