205011551 has 4 divisors (see below), whose sum is σ = 217071072. Its totient is φ = 192952032.

The previous prime is 205011533. The next prime is 205011553. The reversal of 205011551 is 155110502.

It is a happy number.

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 205011551 - 2¹⁸ = 204749407 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 (205011553) 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, 6029735 + ... + 6029768.

It is an arithmetic number, because the mean of its divisors is an integer number (54267768).

Almost surely, 2^205011551 is an apocalyptic number.

205011551 is a deficient number, since it is larger than the sum of its proper divisors (12059521).

205011551 is a wasteful number, since it uses less digits than its factorization.

205011551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12059520.

The product of its (nonzero) digits is 250, while the sum is 20.

The square root of 205011551 is about 14318.2244360116. The cubic root of 205011551 is about 589.6479284155.

The spelling of 205011551 in words is "two hundred five million, eleven thousand, five hundred fifty-one".