205541551 has 4 divisors (see below), whose sum is σ = 206243352. Its totient is φ = 204839752.

The previous prime is 205541537. The next prime is 205541561. The reversal of 205541551 is 155145502.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 205541551 - 2⁷ = 205541423 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 (205541561) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 350461 + ... + 351046.

It is an arithmetic number, because the mean of its divisors is an integer number (51560838).

Almost surely, 2^205541551 is an apocalyptic number.

205541551 is a deficient number, since it is larger than the sum of its proper divisors (701801).

205541551 is an equidigital number, since it uses as much as digits as its factorization.

205541551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 701800.

The product of its (nonzero) digits is 5000, while the sum is 28.

The square root of 205541551 is about 14336.7203711309. The cubic root of 205541551 is about 590.1556144156.

The spelling of 205541551 in words is "two hundred five million, five hundred forty-one thousand, five hundred fifty-one".