205121549 has 4 divisors (see below), whose sum is σ = 215917440. Its totient is φ = 194325660.

The previous prime is 205121537. The next prime is 205121551. The reversal of 205121549 is 945121502.

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 205121549 - 2⁴ = 205121533 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 (205121509) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5397917 + ... + 5397954.

It is an arithmetic number, because the mean of its divisors is an integer number (53979360).

Almost surely, 2^205121549 is an apocalyptic number.

It is an amenable number.

205121549 is a deficient number, since it is larger than the sum of its proper divisors (10795891).

205121549 is a wasteful number, since it uses less digits than its factorization.

205121549 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10795890.

The product of its (nonzero) digits is 3600, while the sum is 29.

The square root of 205121549 is about 14322.0651094736. The cubic root of 205121549 is about 589.7533671837.

The spelling of 205121549 in words is "two hundred five million, one hundred twenty-one thousand, five hundred forty-nine".